preview all symposia

2015 Fall

Materials and devices for energy and environment applications


Materials for energy storage and conversion

Scientists of different communities exploring the new possibilities for materials for energy storage & conversion through their investigation. Hence, there should be E-MRS symposium dedicated to the connection between theory and experiments including both academia and industry.


The prolific growth of energy demand all over the world can be procured by the renewable energy harvesting and storage. Various new materials promise great potential for helping to solve important technological challenges in energy efficiency, storage and the conversion of renewable and sustainable energy. However, performing experiments in the laboratory scale can be quite expensive to test wide range of materials and their properties, which paves the way of computer aided theoretical prediction. Thus materials modeling come into the picture of our daily scientific life. In this symposium, computational and experimental materials scientists working both in academia and industrial environment throughout the world can discuss profoundly the future of materials for energy applications. Leading world experts will provide the insights to the complex science of novel materials for energy applications which will motivate the young researchers in this field.

The proposed workshop aims at bringing together world-leading experts in all these fields to improve interdisciplinary cooperation and overcoming traditional boundaries between scientific disciplines, especially traditional fundamental research and the applied sciences..

The scientific objectives of the proposed workshop are:

  • Bring together researchers from materials science, chemical synthesis, hydrogen, catalysis, photo-catalysis, electro-catalysis, electrochemistry, fuel cells, supercapacitors, and photovoltaics to highlight recent progress and discuss challenges and opportunities in the research and development for energy applications.
  • To discuss possibilities for optimizing the materials properties and device design. The interdisciplinary character of the workshop will help finding solutions for overcoming current drawbacks.
  • Provide opportunity to form new worldwide interdisciplinary collaborations on nanostructured energy materials for the mutual benefit of theoretical, experimental and applied researchers.

Hot topics to be covered by the symposium:

According to the theme of our symposium, which is primly motivated by the fact of energy applications, the following area would be given:

  1. Solar-driven fuels: hydrogen and other organic fuels
  2. Hydrogen production and fuel generation
  3. Hydrogen storage
  4. Organic and Inorganic Solar Cell and Photovoltaic
  5. Hybrid Interfaces for the quest of novel energy efficient materials
  6. Supercapacitors
  7. Fuel cells
  8. Organic and Inorganic Battery Materials
Start atSubject View AllNum.
Authors : Chris G. Van de Walle
Affiliations : Materials Department, University of California, Santa Barbara, California, USA

Resume : First-principles studies of hydrogen interactions with storage materials provide direct insight into the processes of hydrogen uptake and release. The defects involved in kinetics of semiconducting or insulating storage materials are charged, and hence their formation energy is Fermi-level dependent and can be affected by the presence of impurities [1,2]. This provides an explanation for the role played by transition-metal impurities in the kinetics of NaAlH4, LiBH4, MgH2, etc. Desorption of hydrogen is accompanied by decomposition of the storage material and requires not only mass transport of H but also of host atoms. This process is mediated by native defects. We have investigated the structure, stability, and migration enthalpy of native defects based on density functional theory. The results allow us to propose specific mechanisms to explain the observed activation energies. We can also distinguish between formation of defects on the surface versus in the interior of the material, thus explaining the particle-size dependence of the activation energy for decomposition of lithium amide (LiNH2) [3]. Work performed in collaboration with K. Hoang, A. Janotti, A. Peles, and G. B. Wilson-Short. [1] A. Peles and C. G. Van de Walle, Phys. Rev. B 76, 214101 (2007). [2] G. B. Wilson-Short, A. Janotti, K. Hoang, A. Peles, and C. G. Van de Walle, Phys. Rev. B 80, 224102 (2009). [3] K. Hoang, A. Janotti, and C. G. Van de Walle, Angew. Chem. Int. Ed. 123, 10352 (2011).

Authors : Jaroń T,1 Orłowski PA,2 Wegner W,2 Leszczyński PJ,1 Tyszkiewicz M,3 Starobrat A,2 Fijalkowski KJ,1 Grochala W1
Affiliations : 1 Center of New Technologies, Univ. of Warsaw, Zwirki i Wigury 93, 02089 Warsaw Poland; 2 Department of Physics, Univ. of Warsaw, Pasteur 5, 02093 Warsaw Poland; 3 Faculty of Chemistry, Univ. of Warsaw, Pasteur 1, 02093 Warsaw Poland;

Resume : Modus operandi and recent applications will be described of the novel wet protocol for synthesis of dead mass-free hydrogen storage materials. The new metathetic synthetic method has been successfully applied to synthesize mixed-metal borohydrides of Zn [1], Y [2], as well as Sc, Mn, and Mg. Extension to other cations will be discussed. [1] Jaroń T, Orłowski P, Wegner W, Fijałkowski KJ, Leszczyński PJ, Grochala W, ANGEW CHEM INT ED ENGL 54(4): 1236-1239 2015. [2] Jaroń T, Wegner W, Fijałkowski KJ, Leszczyński PJ, Grochala W, CHEM EUR J 21(15): 5689-5692 2015. [3] Manuscript in preparation 2015.

Authors : Pedro Gómez-Romero
Affiliations : Institut Catala de Nanociencia i Nanotecnologia, ICN2 (CSIC-CERCA), 08193 Bellaterra (Barcelona) Spain.

Resume : If nanotechnology is an Enabling Technology, Energy Storage is also increasingly recognized as a key technology to enable our ongoing transition to a sustainable energy model. Electrochemical energy storage will be key to this transition but is still far from optimal. That is why there is still plenty of room for novel types of materials in this trade. Hybrid Nanocomposite Materials offer opportunities for synergy and improved properties. [1] Those formed by electroactive and conducting components are of particular interest for energy storage applications. [2, 5] We have developed a whole line of work dealing with hybrid electroactive and conductive materials for energy storage applications. In this conference we will address some of our recent work towards hybridizing energy storage discussing hybrid electrodes formed by nanocarbons and polyoxometalates or oxides. [3, 4] Furthermore, we will show how hybrids can be designed to take advantage of dual energy storage mechanisms by combining the typical capacitive behavior of supercapacitors with the characteristic faradaic activities of batteries. [5] [1] P. Gomez-Romero Adv.Mater. 2001, 13(3), 163. [2] P. Gomez-Romero et al. J.Solid State Electrochem. 2010 14(11), 1939 [3] V. Ruiz, J. Suárez-Guevara, P. Gomez-Romero Electrochem. Comm. 2012, 24, 35. [4] J. Suarez-Guevara, V. Ruiz and P. Gomez-Romero J.Mat.Chem.A, 2014, 2, 1014. [5] D.P. Dubal, V.Ruiz, O.Ayyad, P.Gomez-Romero Chem.Soc.Rev.2015 44(7):1777-90

Authors : Dawn Thompson*(1,2), David Rooney(1), Jorge Kohanoff(2), Gareth Tribello(2)
Affiliations : 1) School of Chemistry and Chemical Engineering, Queen's University Belfast, Stranmillis Road, Belfast, BT9 5AG, UK, 2) Atomistic Simulation Centre, Queen's University Belfast, Belfast BT7 1NN, UK

Resume : The growing demand for energy on the one hand and climate change, which is closely related to increased energy consumption, on the other, have become central issues worldwide. The present investigation aims at identifying potential ways in which renewable energy can become more appealing and efficient by storing the energy produced, for example by a wind turbine or by residual heat, so that energy is readily available for the consumer in both peak and off peak hours. Amongst the many possibilities, we focus here on nanoparticles within a fluid, i.e. a nanofluid, as a means to store latent heat that is produced for example by a renewable source. Over the past decade nanoparticles have shown the potential to enhance the thermal conductivity of base fluids such as water, ethylene glycol and engine oil, in some cases quite dramatically. The idea here is to embed nanoparticles within a base fluid undergoing a phase change, such as paraffin wax, in order to improve the characteristics of the charge/discharge cycle. Here we aim at understanding the reasons as to when and why nanoparticles enhance thermal conductivity, with the long-term aim of optimizing the process. This is being done by combining experiments and simulation. The experiments are performed in a controlled and systematic way, by varying the type of nanoparticle and fluid as well as nanoparticle concentration, while maintaining the same external conditions and measuring properties using the same experimental setup and apparatus. The modeling is carried out using molecular dynamics simulations with empirical force fields in a variety of situations. The present focus is in graphene sheets and flakes in water, where we can see that hydrophobicity creates a vacuum layer between graphene and water that prevents heat flow in that direction, while heat flow is allowed in the graphene plane and to a lesser extent through the water. This is in contrast to hydrophilic nanoparticles such as TiO2, which allow for heat flow between oxide and water.

10:30 Coffee break    
Authors : Stephane NEUVILLE
Affiliations : TCE

Resume : Some outstanding properties of different type of carbon materials have started to be used for energy storage and conversion and can now be considered for decisive new improvements of many different devices. It is especially concerning electric battery capacity and power with optimized electrode materials, OLED encapsulating and different kinds of renewable energies such as solar cells antireflective encapsulating and tribology of wind/water mills gears. This is now expected to be easier achievable with in-depth comprehensive use of recent progress of corresponding fundamentals, allowing straightforward sorting out and optimization of all involved aspects especially concerning growth mechanisms, defects and structure identification with which carbon structures can now be produced and selected in practice and tailored upon requested property combination. Many solid state aspects are here involved: disorder and mix of different kind of carbon materials which will particularly affect work function, electric, electro-chemical, opto-electronic, and also optical, thermal, diffusion barrier and mechanical properties. We will describe these differentiated aspects and discuss some examples showing their importance on achievement of improved practical results.

Authors : Langner S.[1], Winkler F.[1], Perea J.D.[1], Machui F.[2], Ameri T.[1], Brabec C.J.[1][2]
Affiliations : [1]Institute of Materials for Electronics and Energy Technology (i-MEET), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), D-91058 Erlangen, Germany, [2]Bavarian Center for Applied Energy Research (ZAE Bayern), D-91058 Erlangen, Germany

Resume : Halogenated solvents, such as chlorobenzene, chloroform or o-dichlorobenzene are widely used solvents for solution processed organic solar cells (OSC), but these liquids are harmful to the environment and the human body. Therefor the development of non-toxic photovoltaic inks is a required step towards industrial fabrication of organic photovoltaics. Here, the Hansen solubility parameters (HSP) analysis is used to find suitable solvent blends for various organic semiconductors. In the first step, we determine the HSP of selected organic semiconductors, namely, the star-shaped D-π-A tris{4-[5″-(1, 1-dicyanobut-1-en-2-yl)-2,2′-bithiophen-5-yl]phenyl}amine N(Ph-2T-DCN-Et)3 small molecule, the diketopyrrolopyrrole-based polymer pDPPT-TT and fullerene derivative [6,6]-phenyl-C71-butyric acid methyl ester (PC70BM) and measured the solubility of binary and ternary green solvent blends to confirm the Hansen solubility theory. Next, we used the HSP database and a self written Matlab code to design optimum solvent systems out of 11 000 binary, 550 000 ternary and 20 Mio quaternary green and environmentally friendly solvent combinations. Third, we investigated the most promising solvent combination by engineering organic solar cell devices and analyzed their performance compared to halogen based OSCs.

Authors : K. Kirievsky, M. Kaller, G. Komisarchik, I. Cohen, D. Fuks, Y. Gelbstein
Affiliations : Ben Gurion University of the Negev, Beer Sheva, Israel

Resume : Thermoelectric energy based on a direct conversion of heat (or thermal gradient) into electricity is one possible solution for the problem of affordable, environmentally clean energy. A number of compounds have been investigated in the search for potential thermoelectric materials, including the half-Heusler (HH) and PbTe-type alloys, capable of operation at elevated temperatures with adequate chemical, structural and mechanical stability. Due to relatively easy techniques of alloying of these materials with different elements substituting for its constituents, new ways are considered to manage their conductivity properties. A perspective way to improve the desired properties can be approached by using nanostructured materials. The concept of nano-structuring of thermoelectric materials has drawn much attention primarily due to the prediction that quantum confinement of charge carriers in low dimensional structures within a given matrix could drastically increase the Seebeck coefficient together with a significant decrease of the thermal conductivity, leading to enhancement of figure of merit. We report the latest results of ab-initio calculations aimed at developing the consistent scheme for determining the role of impurities that may change the type of conductivity in two attractive thermoelectric classes of materials. It is demonstrated that alloying of PbTe with small amount of Na substituting for Pb leads to p-type conductivity, while Cl substituting for Te makes PbTe an n-type material. Similar calculations for TiNiSn demonstrate that alloying with Cu makes the material of n-type, and alloying with Fe leads to p-type conductivity. It is shown also that for nano-grained materials the n-type conductivity should be observed. The effect of impurities segregating to the grain boundaries in nano-structured materials is also discussed.

Authors : Aparabal Kumar, P. Banerji
Affiliations : Materials Science Centre, Indian Institute of Technology Kharagpur, Kharagpur - 721302, West Bengal, India

Resume : Cu3SbSe4 is one of the thermoelectric materials synthesized with elements abundant in earth crust and shows promising thermoelectric properties above room temperature (300 - 650 K). Polycrystalline Cu3SbSe4 ingot with high phase purity was prepared with melt growth technique followed by spark plasma sintering (SPS) at 300 °C and 65 MPa for 5 min. The resultant samples were annealed in vacuum furnace at different sintering time to study the effect of grain growth on thermoelectric properties. Structural characterizations were performed to study the phase purity, crystal structure and crystallite size of the sample. Electrical and thermal transport properties were investigated from 300 to 600 K to study thermoelectric properties. Electrical transport properties were explained using single parabolic band model considering the acoustic phonon scattering approximation. It was found that the increase in annealing time leads to increase in electrical conductivity and effective mass. The electrical resistivity and thermal conductivity decrease monotonically with increase in temperature for all the samples. Thermopower represents that the major charge carriers are hole and contributed by Cu deficiency. Small decrease in its value above 550 K shows thermal excitation of charge carrier above that temperature.

Authors : Daniel I. Bilc 1-2, Geoffroy Hautier 3, David Waroquiers 3, Gian-Marco Rignanese 3, and Philippe Ghosez 1
Affiliations : 1 Département de Physique, Université de Liège, 4000 Liège, Belgium; 2 National Institute for Research & Development of Isotopic & Molecular Technologies, Ro-400293 Cluj-Napoca, Romania; 3 Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium

Resume : Thermoelectrics are promising to address energy issues but their exploitation is still hampered by low efficiencies. So far, much improvement has been achieved by reducing the thermal conductivity but less by maximizing the power factor. The latter imposes apparently conflicting requirements on the band structure: a narrow energy distribution and a low effective mass. Quantum confinement in nanostructures or the introduction of resonant states were suggested as possible solutions to this paradox but with limited success. We propose an original approach to fulfill the seemingly conflicting requirements within the same electronic band of certain bulk semiconductors. The approach exploits the highly-directional character of some orbitals to engineer the band structure and produce a type of low-dimensional transport similar to that targeted in nanostructures, while retaining isotropic properties [1]. Using first-principles calculations, the theoretical concept is demonstrated in Fe2YZ Heusler compounds, yielding power factors 4-5 times larger than in classical thermoelectrics. Our findings are totally generic and rationalize the search of alternative compounds with a similar behavior. Realizing such low-dimensional transport in bulk isotropic compounds is totally exotic and relevant also in the context of photovoltaic, electronic, or superconducting applications. 1. D. I. Bilc, G. Hautier, D. Waroquiers, G. M. Rignanese, and Ph. Ghosez, Phys. Rev. Lett. 114, 136601 (2015).

12:30 Lunch break    
Authors : Subhendra D. Mahanti
Affiliations : Department of Physics and Astronomy Michigan State University East Lansing, MI 48824, USA

Resume : Energy is one of the several grand challenges facing the 21st century society. The current worldwide production of power is ~18 TW and is expected to grow to ~30 TW by 2050. Against this huge demand of power, known supply of fossil fuel (oil and gas) is rapidly shrinking and recovering fuels from new sources are becoming increasingly dangerous and environmental unfriendly. Thus there is an urgent need to both develop and increase the use of renewable sources of energy and also to increase the efficiency of current power generation. In the latter context thermoelectricity can play an important role in waste-heat recovery and power production. In this lecture, I will first talk very briefly about the history of thermoelectrics, its classical period and renaissance it went through before 1970. I will then discuss new and not so new ideas like quantum confinement, electron crystal phonon glass, nanostructuring, hierarchical structures, strong anahrmonicity, energy filtering etc. and how they have impacted the field of thermoelectrics during the last several decades to achieve higher efficiency. I will then end with some of the challenges facing this field and attempts to overcome them. *Acknowledge past support from U.S. Department of Energy, Office of Basic Energy Sciences. Work done in collaboration with my past graduate students Dr. Dat Thanh Do and Dr. Khang Hoang

Authors : Albert Figuerola,*,1,2 Mariona Dalmases,1,2 Pau Torruella,2,3 Sònia Estradé,2,3 Francesca Peiró,2,3 Maria Ibáñez,4 Andreu Cabot,5,6 Jordi Llorca,7 Víctor Fernàndez-Altable 2
Affiliations : 1Inorganic Chemistry Department, University of Barcelona (Spain); 2Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona (Spain); 3Laboratory of Electron Nanoscopies (LENS)-MIND/IN2UB, Electronic Department, University of Barcelona (Spain); 4Eidgenössische Technische Hochschule Zürich, ETH Zürich (Switzerland); 5Catalonia Energy Research Institute (IREC) (Spain); 6Institució Catalana de Recerca i Estudis Avançats (ICREA) (Spain); 7Institute of Energy Technologies and Centre for Research in NanoEngineering, Technical University of Catalonia (Spain)

Resume : Silver selenide (Ag2Se) is a heavy metal-free narrow band-gap semiconductor with tunable emission in the second near-infrared window with interesting applications in bioimaging. [1] Additionally, its high electronic and ionic mobility and its low thermal conductivity make it also particularly appealing as a thermoelectric material for energy conversion. [2] On the other hand, complex semiconductor-based nanocrystals such as hybrids or ternary nanostructures are currently devised as efficient materials for energy conversion technologies. [3] In spite of this, the synthesis and study of compositionally-controlled hybrid Ag2X-based nanocrystals still remains a challenge. In this work we present a general, reproducible and scalable method for the synthesis of Au-Ag2X hybrid nanocrystals. The exhaustive structural characterization of the samples indicated the formation of the dimeric nanoparticles as well as the occurrence of high diffusion phenomena of Au+ ions through the Ag2X lattice at room temperature. This low energy barrier process induces the formation of novel and compositionally-controlled Au-Ag3AuX2 hybrid nanocrystals with modified properties. The experimental conditions dictating the formation of either the binary or ternary hybrid systems have been identified. Prototype thermoelectric devices were fabricated: the results show the enhanced thermal-to-electrical energy conversion of the hybrid system with respect to single Ag2Se nanoparticles, and evidence the potential of these new nanostructures for the development of alternative renewable energies. [1] Dong et al. Chem. Mater. 2013, 25, 2503–2509. [2] Xiao et al. J. Am. Chem. Soc. 2012, 134, 4287–4293. [3] Kovalenko et al. ACS Nano 2015, 9, 1012-1057.

Authors : N.M. White, M. Burton, E. Koukharenko, I.Nandhakumar
Affiliations : University of Southampton

Resume : There is overwhelming evidence that our increasing consumption of fossil fuels and the associated emission of carbon dioxide is leading to climate change. This has brought new urgency to the development of clean, renewable sources of energy. Thermoelectric (TE) materials are an important class of materials that can directly convert thermal waste heat into useful electrical energy. With approximately 15 terawatts of available energy being lost to the environment as heat the potential for TE materials in sustainable waste-heat-recovery systems such as TE power generation is huge. However, barriers exist to the widespread adoption of TE technology which is due to the low efficiency of current TE materials. Clearly a step change in the cost and performance of TE materials is required to make them more economically viable and to promote their wider adoption in a number of application areas. In the current work we propose to achieve this by 1. employing electrodeposition as a low-cost, low-temperature route to the fabrication of highly efficient TE materials from, abundant, non-toxic and cheap materials and by employing soft-template directed nanostructuring to produce TE materials

Authors : Yinghong Hu, Aurélien M. A. Leguy, Mariano Campoy-Quiles, M. Isabel Alonso, Oliver J. Weber, Pooya Azarhoosh, Mark van Schilfgaarde, Mark T. Weller, Thomas Bein, Jenny Nelson, Piers R. F. Barnes, Pablo Docampo
Affiliations : Ludwig-Maximilians-Universität, München, 81377, Germany; Imperial College, London, SW7 2AZ, United Kingdom; Institut de Ciència de Materials de Barcelona, Bellaterra, 08193, Spain; University of Bath, Bath, BA2 7AY, United Kingdom; King’s College, London, WC2R 2LS, United Kingdom

Resume : Solar cells composed of methylammonium lead iodide (MAPI) are notorious for their sensitivity to moisture, which limits the device lifetime. Ensuring the long-term stability of perovskite solar cells under operational conditions is crucial for their implementation into large-scale applications. Therefore, the degradation mechanisms occurring within the perovskite material upon exposure to moisture need to be elucidated. Here, we show that MAPI undergoes a stepwise transformation into two species of transparent hydrated MAPI crystal phases upon exposure to moist air at room temperature, and that these phase changes can be fully reversed when the material is subsequently dried. We have modeled the structural and optical data on thin films and single crystals to determine the time-dependent changes to MAPI films exposed to moisture. Our results indicate that the conversion into the monohydrate phase occurs isotropically within the granular perovskite film, suggesting rapid transport of water molecules along grain boundaries. The reverse reaction was observed in the successive dehydration of hydrated MAPI single crystals under low air humidity. In contrast to water vapor, the presence of liquid water led to the irreversible decomposition of MAPI to form lead iodide. Finally, we show that the same process occurs state-of-the-art perovskite solar cells. Vapor phase hydration of a device without encapsulation resulted in a more than 90 % drop in short circuit photocurrent and an approximately 20 % loss in open circuit potential. However, the device performance was fully recovered after the cell was dried under a nitrogen flow for 6 hours. Based on our observations, we suggest that devices which exhibit a dramatic decrease in performance due to the formation of a thin hydrated layer at the grain boundaries within the MAPI layer may be recovered by a simple drying step at ambient conditions.

Authors : Mohamad M. Ahmad
Affiliations : Department of Physics, College of Science, King Faisal University, Al-Ahsaa 31982, Saudi Arabia

Resume : Lithium ion batteries are based on flammable organic/polymer Li+ ion conductors as electrolytes, leading to several drawbacks. Therefore, using ceramic/inorganic Li+ solid electrolytes has been proposed for the development of solid-state Li+ batteries. Li5La3M2O12 (M= Ta, Nb) based Li+ conducting garnets are promising candidates as solid electrolytes. However, the ionic conductivity of these materials is in the 10^-6 S/cm, which is still low for practical applications. Conductivity enhancement could be achieved by chemical substitutions on La or M sites such as in Li6La2BaTa2O12, Li5+2xLa3M2-xAxO12 (A= trivalent cations) and Li7La3Zr2O12 with conductivity value up to ~10^-4 S/cm. The increased conductivity is attributed to the increased concentration of mobile Li+ with increasing Li+ content. Here, with appropriate analysis of the conductivity spectra at different temperatures of several garnet phases, we show that Li+ conductivity enhancement is due to the enhanced mobility of Li+ rather than the concentration of mobile Li+. The enhanced mobility of Li+ is due to the re-distribution of Li+, so that the occupancy of Li+ in tetrahedral sites decreases and the occupancy of Li+ in octahedral sites increases with increasing Li+ content. This re-distribution process creates more vacant tetrahedral sites available for Li+ diffusion. We suggest that, chemical substitutions on Li sites by divalent or trivalent cations will create more vacancies, leading to increased conductivity.

15:30 Coffee break    
Authors : Konstantin Glaser, Stefan Gärtner, Christian Sprau, Felix Nickel, Sivaramakrishnan Sankaran, Alexander Colsmann
Affiliations : Karlsruhe Institute of Technology (KIT), Lichttechnisches Institut, Engesserstrasse 13, 76131 Karlsruhe, Germany

Resume : The industrial fabrication of organic solar cells is often hampered by toxic solvents that require strong safety precautions. Whereas the use of chlorinated solvents or toxic hydrocarbons is feasible in the lab, their use in large scale printing processes would lead to enormous operational costs, which conflicts with the goal of cost effective production. In this work, we present efficient organic solar cells that were fabricated from non-halogenated solvents. To advance this concept and to enable device fabrication from non-toxic solvents, we synthesized organic solar cells entirely from aqueous and alcoholic solvents. For the absorber layer, we disperse, investigate and use P3HT:ICBA nanoparticles in environmentally friendly dispersion agents such as ethanol. In an inverted solar cell architecture with a nanoparticulate P3HT:ICBA layer the power conversion efficiency of 5% nearly matches the performance of reference devices that were fabricated from dichlorobenzene. We further demonstrate that this device fabrication concept is well suited for upscaling.

Authors : Chun-Guey Wu
Affiliations : National Central University

Resume : lanar heterojunction organic-perovskite hybrid solar cell is one of the most promising photovoltaic architecture to achieve high efficiency with low temperature process. A new two-step solution process to synthesis high quality perovskite film at room temperature was disclosed. Combining with smooth PEDOTLPSS hole transport layer and high mobility electron transport (PC71BM) layer, the planar heterojunction perovskite-PC71BM solar cell achieves the power conversion efficiency above 16%. This champion cell shows no current hysteresis both in voltage scan directions and rates.. The crystalline perovskite film was made by first spin-coating PbI2 film then adding CH3NH3I via spin-coating. The growth and purity of perovskite film can be manipulated individually, providing a simple and reproducible way to fabricate perovskite based solar cells via low temperature solution process in an ambient atmosphere

Authors : N. von Morzé1, S. Wiesner1, A. R. Jeong1, T. Dittrich1, S. Brunken2, S. Vatavu,1 C. A. Kaufmann2, M. Ch. Lux Steiner1, M. Rusu1
Affiliations : 1 Institute Heterogeneous Materials Systems , Helmholtz-Zentrum Berlin für Materialien und Energie, Lise-Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany 2 Institute Competence Centre Photovoltaics Berlin (PVcomB), Helmholtz-Zentrum Berlin für Materialien und Energie, Lise-Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany

Resume : We demonstrate hybrid solar cells based on small organic molecules of Zinc-Phthalocyanine (ZnPc) and fullerene C60 and inorganic chalcopyrite CuInSe2 thin films. The materials combination relates to a suitable optical and electronic properties for heterojunction solar cells as well as to an effective dissociation of excitons at organic/organic and organic/inorganic interfaces. The effectiveness of the exciton dissociation was investigated by surface photovoltage measurements on ZnPc:C60 blend layers and CuInSe2/C60, CuInSe2/ZnPc and CuInSe2/ZnPc:C60 structures. Superior SPV signals among organic/inorganic interfaces were recorded on the latter stack. The application of this stack in Mg:Ag (12nm)/organic (100 nm)/CuInSe2(1.7 um)/Mo (300 nm)/glass solar cells resulted in highest efficiencies of 2.16%. The devices with just C60 layers in contact with CuInSe2 thin films showed efficiencies of 1.93%. The quantum efficiency (QE) of both devices was extended in the infrared region from 760 nm by more than 400 nm when compared to pure ZnPc:C60 organic solar cells. The devices with the CuInSe2 / ZnPc:C60 stack showed in addition better QE in the wavelength region of 350-550 nm. The analysis of the QE measurements point to a reduced effective carrier collection length compared to their inorganic counterparts related to narrower space charge region width. This impediment could be however eliminated by the preparation of solar cells with reduced thicknesses.

Authors : Dimitar Kutsarov1, Ilija Rasovic2, Alexandros Zahariadis3, Argiris Laskarakis3, Kirsten Bruchlos4, Kyriakos Porfyrakis2, Christopher Mills1, Brett Fisher1, Stergios Logothetidis3, Sabine Ludwigs4, S. Ravi P. Silva1
Affiliations : 1Nanoelectronics Centre, Advanced Materials Institute, University of Surrey, Guildford, Surrey, GU2 7XH, UK; 2Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK; 3Aristotle University of Thessaloniki, Physics Department, Lab for Thin Films-Nanosystems and Nanometrology, GR-54124 Thessaloniki, Greece ; 4IPOC-Functional Polymers, University of Stuttgart, 70569 Stuttgart, Germany

Resume : Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) have been the fruit fly donor and acceptor materials for polymer solar cells (PSCs). The open circuit voltage (VOC) and hence the power conversion efficiency (PCE) for this type of PSC is limited due to the low energy of the lowest unoccupied molecular orbital (LUMO) of PCBM, when considered to the energy level of the highest occupied molecular orbital (HOMO) of P3HT. As a consequence, P3HT:PCBM PSCs show an approximate peak power conversion of 5% but an average PCE value of only about 3%. Using indene-C70 bisadduct (IC70BA) as an acceptor, which exhibits an approximately 0.19 eV higher LUMO level compared to that of PCBM, researchers have reported improved VOC and consequently PCE. Yet, average PCEs for P3HT:ICBA based solar cells remain at approximately 4.5%, typically for small device areas (average 0.09 cm2), unsuitable for real-world applications. Hence, there is need for improved, large area PSCs which can deliver high efficiencies when scaled up to dimensions suitable for commercial applications. Here we describe the optimisation and scale-up of P3HT:ICBA based solar cells for large scale manufacture, suitable for real-world applications. We investigate P3HT:ICBA based PSCs, fabricated using commercially available IC70BA, with the aim to understand the chemistry behind the bisadduct regioisomerism. We examine how the blend morphology and hence PSC performance is impacted by different ICBA regioisomers. We also study thermally induced and solvent mediated physical and chemical alterations of P3HT, ICBA, and their blend. In this regard, we are the first group to report an investigation of the effect of solvent- and thermal annealing on the vertical D-A material distribution using spectroscopic ellipsometry and contact angle measurements. We found that the formation kinetics of the P3HT:ICBA layer plays a critical role for achieving high photovoltaic efficiencies, and is strongly correlated to the D-A interpenetrating network morphology, which is a function of the P3HT crystallinity and IC70BA segregation. As such, under optimised fabrication conditions and using the spin-coating technique, we fabricate large area (0.43 cm2) P3HT-based PSCs with PCEs averaging at 5.7% and peaking at 6%. Progressing to the fabrication of PSC modules, suitable for commercial application, we also fabricated single slot-die coated PSCs with an active area of 5.6 cm2. Overcoming various challenges associated with the coating process and understanding the relation between fabrication conditions such as web speed, flow rate, gap between the meniscus of the slot-die head and the sample, and the fabrication temperature, we achieved highly reproducible homogeneous films for all PSC materials. Furthermore, our fabrication process was applied using other D-A photoactive blends, with low band gap polymers such as PCDTBT. After connecting single solar cells in series, we illustrate a route to fabricate single layer modules on a large scale, having a photoactive area of 33.6 cm2. Our coating process is furthermore directly compatible with industrial scale manufacturing, allowing high throughput fabrication of PSCs using the slot-die coating technique on a roll-to-roll process.

Authors : Simrjit Singh, Neeraj Khare
Affiliations : Nano Functional Oxide and Superconductivity Laboratory,Physics Department, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India.

Resume : Photoelectrochemical water splitting is an advanced chemical process for the generation of hydrogen (H2) using solar energy. Since the discovery of photoelectrochemical water splitting using TiO2 semiconductor, many metal oxide semiconductors have been extensively used as photoelectrodes for water splitting. However, due to the larger band gap of most of the oxide semiconductors, they use only UV light which is only 5 % of the solar spectrum incident on the earth’s surface. Therefore, for the generation of hydrogen on a larger scale, there is a need to develop visible light active photoanode materials for water splitting. Among visible light active semiconductor materials, CdS has attracted much attention due its optical band gap of 2.4 eV and has an optimal position of band edges for splitting of water into hydrogen. However, the phototelectrochemical activity of CdS is limited by various factors such as (i) CdS is unstable in aqueous solution and readily become deactivated through photocorrosion and (ii) high rate of charge carrier recombination. In order to address these limitations and improving the solar energy conversion efficiency of CdS, we have synthesized CdS/CoFe2O4 (CdS/CFO) core/shell nano heterostructure having a type-II band-edge alignment and coupled it with reduced graphene oxide (RGO). CFO has a band gap of 1.8 eV and is very much chemically and thermally stable. The key strategy in the designing of CdS/CFO/RGO nanostructure is to achieve the efficient transfer of electrons within the coupled components for enhancing the activity for phototelectrochemical water splitting and also to protect CdS from photocorrosion in aqueous solution using CFO as an outer layer of CdS. CdS/CFO/RGO nanostructure is synthesized by self assembly using a soft chemical method. First, CdS nanorods are synthesized by hydrothermal method using cadmium nitrate and thiourea in 50 ml ethylenediamine. Before growing CFO, the surface of the CdS nanorods is functionalized using a suitable functionalizing agent which leaves the surface of the nanorods with negatively charged ions. The core/shell nanostructures of CdS/CFO are obtained by using hydrothermal technique by keeping functionalized CdS nanostructures in cobalt nitrate and iron nitrate solution. The hydrothermal reaction is carried out in Teflon lined stainless steel autoclave at 120 °C for 10 hours. Afterwards, the synthesized CdS/CFO core/shell nanostructure is coupled with RGO by using chemical method. The synthesized CdS/CFO/RGO nanostructures are characterized by X-ray diffraction, UV-visible spectroscopy and Transmission electron microscopy. Photoelectrochemical measurements are performed using a three electrode electrochemical cell assembly. The thin films of CdS, CdS/CFO and CdS/CFO/RGO nanostructures are deposited by spray coating technique and are used as working electrodes. The CdS/CFO/RGO nanostructured film shows significant improvement in the photocurrent density and the incident photon conversion efficiency as compared to CdS and CdS/CFO nanostructure films. The enhancement in the photoelectrochemical activity in CdS/CFORGO nanostructure is due to the faster charge transfer between the coupled components and thus improves the overall photocurrent conversion efficiency.

Authors : Kun-Mu Lee 1,2*, Kai-Hung Wang 2, Chun-Guey Wu 1
Affiliations : 1 Research Center for New Generation Photonics, National Central University, Taoyuan 32001, Taiwan, ROC 2 Department of Chemical and Material Engineering, National Central University, Taoyuan 32001, Taiwan, ROC

Resume : Since organolead halide perovskite has been used as light absorber in solid-state photovoltaic and shows a high efficiency in 2012, it has attracted great interest and eventually led the paradigm shift in photovoltaic technology. In this study, the planar heterojunction solar cell (glass/ITO/PEDOT:PSS/CH3NH3PbI3/PCBM/Ag) has already demonstrated by a fully solution-based process and shows an impressive cell performance. The use of different ratios mixed solvent of γ-butyrolactone (GBL) and dimethylsulphoxide (DMSO) dissolve PbI2 and CH3NH3I for one step process and followed drop-casting by different solvents (more than 10 solvents). The relationship between drop-casting solvent parameters such as boiling point, dielectric constant, dipole moment and donor number and performance of perovskite solar cells has been investigated. Finally, we can get a dense and uniform CH3NH3PbI3 layer as light absorber for the perovskite solar cell using drop-casting solvents with boiling point more than 100 oC, low dielectric constant (< 10), low dipole moment (< 3) and low donor number (< 4). We also study the effects of volume of drop-casting solvent, baking temperature and thickness of perovskite layers, and have the remarkably improved solar cells with a conversion efficiency of 13.4% under 100 mW/cm2 and no hysteresis.

Authors : Kun-Mu Lee 1,2*, Chun-Guey Wu 1
Affiliations : 1 Research Center for New Generation Photonics, National Central University, Taoyuan 32001, Taiwan, ROC; 2 Department of Chemical and Material Engineering, National Central University, Taoyuan 32001, Taiwan, ROC

Resume : Counter electrodes (CE) containing high transmittance Pt nanoparticles are prepared at an ambient temperature of 40 0C for dye sensitized solar cell (DSSC) application. The deposited nano-Pt material is characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Symmetrical cell fabricated with CE containing 1.8 wt% nano-Pt showed high exchange current density and low charge transfer resistance, as confirmed by Tafel analysis and electrochemical impedance study (EIS) respectively. The Ti foil sub-module DSSC (10 cm?10 cm) having such CE exhibited a high conversion efficiency of 7.47% at an illumination of 100 mW/cm2. Further, the DSSC maintained >90 % of the baseline efficiency after more than 2000 hrs continuous one sun light soaking at 60 oC.

Authors : Taekjib Choi, Chul min Youn, Heejin Lee
Affiliations : Hybrid Materials Research Center and Department of Nanotechnology and Advanced Materials Engineering, Sejong University, 143-747

Resume : Transition metal oxides are attractive as photoelectrodes for solar water splitting because of their stable photochemical activity in aqueous solutions. However, photoelectrochemical performance is usually limited by poor charge carrier separation. Thus, Hybrid photoelectrodes based on two-dimensional nanomaterials/ semiconducting ferroelectric materials offer promising potential for achieving efficient solar water splitting by enhancing charge conduction and promoting photogenerated-charge carrier separation due to spontaneous electric polarization leading to an increase in the effective electric field. In this study, we have fabricated two-dimensional nanomaterials decorated BiFeO3 thin films as hybrid electrodes. The structural and optical properties of single and hybrid electrodes were comparatively characterized. The hybrid electrodes exhibited a stronger absorption of visible light and produced a higher photocurrent than that of single electrode. For hybrid electrodes, photoelectrochemical characterization demonstrated a large enhancement of the interfacial charge transfer kinetics as well as an efficient charge carrier separation, which greatly contributed to the improved photoelectrochemical performances. In addition, we will discuss poling effect of electric polarization on interface reduction/oxidation (REDOX) through electrolyte ions. Therefore, our results provide useful information for developing highly efficient hybrid photoelectrodes for solar water splitting.

Authors : Hyunuk Kim, Young-Ju Lee, Yoonjong Yoo
Affiliations : Korea Institute of Energy Research

Resume : Carbon papers (CPs) with high electrical conductivities and gas permeabilities have been historically used as gas diffusion layers (GDLs) in proton exchange membrane fuel cells (PEMFCs). CPs with high electrical conductivities are fabricated by the high temperature carbonization of a thermosetting resin, which acts as a binder and makes the CPs brittle to bending. Herein, we report the fabrication of CPs containing a conducting polymer poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) under mild fabrication conditions. These CPs were prepared by combining pristine CP and PEDOT:PSS solutions with ethylene glycol (EG) and graphite powder (GP) and annealing the mixture at 100 C. The CP containing PEDOT:PSS-EG-GP possessed an electrical conductivity higher than that of conventional CPs that were fabricated by high-temperature carbonization of a thermosetting resin. The mechanical stability of the CPs containing PEDOT:PSS-EG-GP was much higher than that of conventional CPs because of the flexibility of the conducting polymer. Moreover, the novel CP maintained its electrical conductivity after bending. We evaluated the performance of a single-cell for used as a PEMFC in which the GDL was a CP containing PEDOT:PSS-EG-GP.

Authors : Mariona Dalmases* (1,2), Albert Figuerola (1,2), Pau Torruella (2,3), Sònia Estradé (2,3), Francesca Peiró (2,3), Maria Ibáñez (4), Andreu Cabot (5,6), Jordi Llorca (7), Víctor Fernández-Altable (2)
Affiliations : (1) InorganicChemistry Department, University of Barcelona (Spain); (2) Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona (Spain); (3) Laboratory of Electron Nanoscopies (LENS-MIND/IN2UB), Electronic Department, University of Barcelona (Spain); (4) Eidgenössische Technische Hochschule Zürich, ETH Zürich (Switzerland); (5) Catalonia Energy Research Institute (IREC) (Spain); (6) Institució Catalana de Recerca i Estudis Avançats (ICREA) (Spain); (7) Institute of Energy Technologies and Centre for Research in NanoEngineering, Technical University of Catalonia (Spain)

Resume : Thermoelectric devices, since their ability to convert heat into electricity, have attracted great interest in recent years as potential renewable energy convertors in order to use residual heat (from sunlight, chemical reactions, nuclear decay, etc.) and minimise the production of green house gases and the subsequent global warming effects. Silver selenide is one of the studied materials in this field owing to its good thermoelectric behaviour and its crystalline phase dependant electronic properties: it behaves as a narrow bandgap semiconductor at low temperature (orthorombic phase) and as a superionic conductor at high temperature (cubic phase). In this project we present an hybrid nanomaterial based on Ag2Se for the enhancement of its thermoelectric response. Specifically, a dimer-like nanostructure of Au-Ag3AuSe2 synthesised by heterogeneous nucleation and growth at room temperature of gold on the pre-synthesised Ag2Se nanoparticles surface and simultaneous diffusion of Au(I) cations in its structure. The characterization from HRTEM, XRD and SAXS verifies the size, the shape and the composition of the nanostructured material and the thermoelectric measurements demonstrate the improvement of the figure of merit (ZT) and the power factor of it in comparison to silver selenide.

Poster Session : -
Authors : Duc-The Ngo, Roberto Scipioni, Søren Bredmose Simonsen, Peter Stanley Jørgensen, and Søren Højgaard Jensen
Affiliations : DTU Energy, Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde, Denmark

Resume : We present here an investigation of the chemical and morphological degradation mechanisms in a LiFePO4/Carbon black (LFP/CB) cathode in Li-ion batteries by means of high-resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM). Two laboratory LFP/C cathodes were prepared from LFP, carbon black, CB (super carbon C65)and polyvinylidene fluoride (PVdF) with a ratio of 80:10:10. A “fresh” and an “degraded” cathode were prepared by 2 and 100 charge/discharge cycles respectively at 0.1C using lithium metal foil counter electrodes and a glass fiber separator soaked with a standard 1M LiPF6 in 1:1 EC/DMC electrolyte. After cycling, the two batteries were disassembled in a glove box and the fresh and the degraded cathode were embedded in silicon resin. After curing of the resin, TEM lamellar specimen of the two cathodes was prepared by focused ion beam (FIB) milling. TEM study on pristine LFP nanoparticles and SP shows orthorhombic LFP nanoparticles with average size of 200 nm and SP nanoparticles with graphitic sheets in average size of 30 nm, respectively. HRTEM imaging indicates that crystal structure of LFP particles still remain in the degraded cathode but a number of coating layers including amorphous carbon and solid electrolyte interphase (SEI) layers have developed on the particles surface. In the degraded cathode a part of the SP transformed from graphite crystal to an agglomerated amorphous structure which most likely contributes to the cathode degradation by reducing electrical conductivity and percolation. X-ray energy dispersive spectrum (EDS) mapping of elemental composition using STEM reveals the accumulation of fluoride (F) phase on the particles surface suggesting that SEI layers are presumably F-contained phases.

Authors : Sergei Vassel
Affiliations : Rostov branch of MSUTU

Resume : The suggested electrochemical way of low-potential heat conversion into electricity is consist of two stages: 1.separation of sodium hydroxide solution into low and high concentration solutions in temperature gradients 2. electrical energy generation in concentration galvanic cell with Fe/Fe(OH)2 or Ag/Ag2O electrodes. In contrast to the traditional concentration galvanic cells, where the potential difference depends on the logc1/c2, in sodium hydroxide solutions we have practical linear dependence of the electrode potential on the NaOH concentration. We have this effect because galvanic cell uses an exothermic reaction of NaOH dissolving in the water. Earlier we suggested to use distillation to obtain concentration difference. During distillation there is no direct heat contact between heater and cooler. The heat transfer is carried out by evaporation of water from the more concentrated solution and condensing it into a less concentrated solution. Thus, transferring the heat we carry out a useful reaction. So, using distillation we could obtain the highest efficiency (under some conditions it could be near Carnot cycle efficiency). But distillation in low temperature gradients is rather slow process, even in vacuum. So, we work out another way of separation high concentration sodium hydroxide solution from low concentration solution. It is based on different solubilities of sodium hydroxide in water at different temperatures (or, more correctly, NaOH*H2O melting )

Authors : O. Morozov, I. Neklyudov, V. Zhurba, V. Progolaieva, A. Кuprin, V. Оvcharenko, O. Galitskiy
Affiliations : National Science Center ?Kharkiv Institute of Physics and Technology?, 1, Akademichna St.,UA-61108, Kharkiv, Ukraine.

Resume : Magnesium-based alloys are promising in the view of present-day requirements to the metal-hydride hydrogen storage systems. The plasma evaporation-sputtering method was applied to make composite materials of the Al-Ti system (the method of atom-by-atom mixing of components). The ion-implanted deuterium desorption temperature variations as a function of the component concentration and the ion implantation dose were studied. A low magnesium concentration and, consequently, a high titanium concentration in the composite are revealed in the deuterium thermal desorption (TDS) as a single peak with a maximum temperature at 800-950 K depending on the implanted deuterium dose and composite composition. Increase of the magnesium concentration in composites leads to the significant change in the deuterium TDS that results in the sharp decrease of the deuterium desorption temperature for Al85 хTiх composites. It has been established that, by introducing Ti into Al, the deuterium desorption temperature can be appreciably decreased (to 300-450 K) in comparison with the case of deuterium desorption from titanium and aluminium. A step-like form of the curve of deuterium desorption temperature evidences on the presence of two different structure states of the Al-Ti system depending on the ratio of components. The deuterium temperature decrease can be caused by filamentary inclusions formed, in the process of composite making and annealing, by the component titanium atoms providing the deuterium diffusion from the sample at a lower temperature (channels for deuterium diffusion through the surface barrier). A necessary high diffusion mobility of deuterium is provided by the amorphous/nano state of samples.

Authors : Aferdita Priftaj Vevecka
Affiliations : Polytechnic University of Tirana Department of Physics Sheshi "Nene Tereza", N.4, Tirana, Albania

Resume : Abstract During the last decades, fabrication of bulk nanostructured metals and alloys using severe plastic deformation (SPD) processing, has been evolving as a rapidly advancing direction of nanomaterials science, aimed at developing materials with new mechanical and functional properties for advanced applications. For the moment the three SPD methods receiving the most attention are Equal-Channel Angular Pressing (ECAP), Accumulative Roll-Bonding (ARB) and High-Pressure Torsion (HPT). These SPD methods lead to very significant grain refinement to the submicrometer or even the nanometer level and have been widely used for a large range of metals and alloys. The aim of the present work, is firstly to present an overview of the most used methods of severe plastic deformation for grain refinement and the production of bulk nanomaterials. In order to examine the potential for using ECAP to refine the grain size and improve the mechanical properties, the commercial 5754 Al alloy, was selected for study. Specimens of commercial 5754 Al alloy were pressed up to 7 passes through the ECAP die. Microstructure observations were realized by Transmission Electron Microscopy (TEM) and mechanical properties were evaluated by microhardness HV and Tensile testing at room temperature. This investigation demonstrated that ECAP was an effective tool for achieving a substantial reduction in the grain size of the commercial 5754 Al alloy. Processing by ECAP through up to 7 passes in the ECAP die, gave a reduction in the grain size and an increase in the microhardness of the alloy, and in the 0.2% proof stress, by a factor of three times. This work and other works too demonstrates the possibility of tailoring the microstructures of metals and alloys by SPD to obtain both high strength and high ductility. Materials with such desirable mechanical properties are very attractive for advanced structural applications.

Authors : Paulina Poniatowska1, Daniel Jastrzebski1, Maciej Bialoglowski1, Dorota Brzuska1, Krzysztof Wozniak2, Roman Gajda2, Slawomir Podsiadlo1
Affiliations : 1 Faculty of Chemistry, Warsaw University of Technology; 2 Faculty of Chemistry, University of Warsaw

Resume : Semiconductors based on or related to tin sulfides, such as SnS, SnS2, and Cu2ZnSnS4, have recently lured the attention of researchers around the world. Having the bandgaps relatively close to the optimum of Shockley-Queisser limit, makes them especially interesting as potential absorbing materials in solar cells. This study reports a method for obtaining single crystals of Sn2S3, with a calculated bandgap of 1.1 eV. The syntheses have been carried out using chemical transport in vacuum. The obtained crystals have been characterized with X-ray diffraction methods, transmission electron microsocpy and Raman scattering spectroscopy.

Authors : Marco Fronzi, Michael Nolan
Affiliations : Tyndall National Institute, UCC, Lee Maltings, Dyke Parade, Cork, Ireland

Resume : The development of highly ionic conductive materials is particularly important for the fabrication of high performance solid oxide fuel cell (SOFCs) operating at intermediate-low temperature (550-900K). At present, the state-of-the- art in SOFC technology requires the cell to operate at temperatures between 1000-1300K and such high operating temperatures require high fabricating and operative costs, since expensive materials for the sealing and inter- connectors are needed. Therefore, to speed up the widespread acceptance of SOFCs, the development of highly conductive materials that can operate at intermediate- low temperatures is imperative. Barium zirconate oxides (BaZrO3) have been the subject of wide interest since they show a high oxygen mobility when crystallised in a perovskite structure.[1,2,3] The role of doping has shown to be crucial since it strongly enhances ion mobility at the bulk level as well as stabilising the cubic structure. Recent observation have shown how, when a structure is subject to an external strain, the conduction properties of the crystal are affected, however the mechanism of ion transport under strain conditions is not yet completely clear. It is crucial, therefore, to shed light on the mechanism of conduction in order to be able to predict the optimal conditions to obtain a maximum conduction enhancement. In this work, first principles Molecular Dynamics simulations have been employed to analyse the proton self-diffusion in BaZrO3 cubic perovskite structure. Simulations have been done at 1300K in order to reproduce the typical fuel cell working conditions. The calculation were carried out for the stoichiometric structure under fully relaxed cell conditions and we studied the effect of both an applied compressive and tensile external strain on the proton motion through the crystal structure and we find a non linear effect of the strain on the proton mobility. An evident enhancing of the diffusion has been found when the lattice is compressed by 2% . On the other hand, a tensile strain seems not to affect the proton migration if compared with the cell under fully relaxed condition. The power spectrum obtained by the velocity-velocity correlation function for the proton has been calculated and it shows no significant variation of vibrational frequencies under strain conditions. [1] Emiliana Fabbri, Daniele Pergolesi and Enrico Traversa, Chem. Soc. Rev.39, 4355-4369, (2009) [2] Q. Zhang, G. Wahnstram M. E. Bjorketun S. Gao, and Wang, E. Phys. Rev. Lett.378, 40-44 (2008) [3] G. Sundell, M. E. Bjorketun, and G. Wahnstram, Phys. Rev. B. 76 , 094301 (2007)

Authors : Marco Fronzi, Michael Nolan
Affiliations : Tyndall National Institute, UCC, Lee Maltings, Dyke Parade, Cork, Ireland

Resume : Modifications of TiO2 are intensively studied as photocatalysts such as solar water splitting or solar CO2 reduction, both of which can produce useful fuels using solar energy. To date, substitutional doping of Ti and/or O sites is the most widely studied approach but suffers from practical problems. We have developed an alternative approach – modification of TiO2 surfaces with nanoclusters of metal-oxides with the aim to Shift light absorption into the visible region Enhance electron-hole separation Provide reactive sites for H2Oor CO2 to interact and O vacancies to form

Authors : C. Alegre*, C. D’Urso, S. Siracusano, E. Modica, C. Lo Vecchio, A.S. Aricò, V. Baglio
Affiliations : Istituto di Tecnologie Avanzate per l’Energia “Nicola Giordano” (CNR-ITAE),

Resume : Electrocatalysts for the oxygen reduction and/or the oxygen evolution reactions play a key role to determine the performance of energy conversion/storage devices, such as fuel cells, electrolysers, regenerative fuel cells or, recently, metal–air batteries. Oxygen electro-oxidation/electro-reduction presents slow kinetics, thus, in order to achieve high current densities, porous electrodes are required. Carbon materials are commonly used to increase the electrode surface area. The main disadvantage is that carbon corrosion processes can occur in particular during the oxygen evolution process at very positive potentials, thus affecting the stability of the catalysts. In this work, several carbonaceous (Vulcan, Ketjenblack) and non-carbonaceous (Ti-based) materials were used as supports for Pd electrocatalysts. The electrochemical investigation of these catalysts for the oxygen reduction and evolution processes was carried out in an alkaline medium. ACKNOWLEDGMENTS: Authors thank “Accordo di Programma CNR-MiSE, Gruppo tematico Sistema Elettrico Nazionale – Progetto: Sistemi elettrochimici per l’accumulo di energia” for the financial support.

Authors : Yong-Duck Chung1,3, Woo-Jung Lee1, Dae-Hyung Cho1, Jae-Hyung Wi1, Won Seok Han1, Jisu Yoo2, Yeonjin Yi2, Je-hyung Seo4, Myung-Woon Choi4
Affiliations : 1Components & Materials Research Laboratory, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea; 2Insitute of Physics and applied physics, Yonsei University, Seoul 120-749, Korea; 3Department of Advanced Device Engineering, Korea University of Science and Technology, Daejeon 305-350, Korea; 4System Development Team, YAS Co., Ltd. Paju-si 413-843, Korea.

Resume : It has been reported that Cu(In,Ga)Se2 (CIGS) exhibits the highest efficiency among all materials for thin-film solar cells. In general, the p–n heterojunction is formed by depositing a thin buffer layer on CIGS. Among buffer materials, Zn-based buffer has been steadily studied because of their beneficial properties, for examples, good transparency with large direct bandgap and less toxicity than Cd-based buffers which are typically used. In this study, we have characterized the interface of p-n heterojunction between Zn-based buffer and CIGS by measuring the impedance spectroscopy (IS) and investigated its influence on the photovoltaic performance with the variation of deposition process. The Zn-based buffer layer was deposited with two types of process. One was the formation of ZnS layer through the sulfurization of Zn film with S cracker and the other was chemical bath deposition (CBD) which was conventionally used. The interfacial properties of p-n heterojunction were investigated as a function of buffer layer thickness for cracking process and the concentration of chemical constituents for CBD process. The equivalent circuit was suggested, consisting of resistance and capacitances about junction interface. From the IS results, we discovered the direct correlation between photovoltaic performance and capacitance values, demonstrating the importance of interfacial quality in terms of the device performance.

Authors : A. Elfakir1,, G. Schmerber2, S. Colis2, A. Belayachi1, A. Dinia2, A. Slaoui3 and M. Abd-Lefdil1
Affiliations : 1 University of Mohammed V- Agdal, Materials Physics Laboratory, P. B. 1014, Rabat, Morocco; 2 IPCMS, CNRS-Université de Strasbourg, 23 rue du Loess, F-67037 Strasbourg cedex 2, France; 3 ICube, CNRS-Université de Strasbourg, 23 rue du Loess, F-67037 Strasbourg cedex 2, France.

Resume : Neodymium and thulium codoped ZnO (NTZO) thin films were deposited on glass substrates by chemical spray pyrolysis method. The influence of both doping concentration on structural, optical and electrical properties were characterized by various techniques. X-ray diffraction (XRD) patterns revealed that all the films have a polycrystalline nature fitting with a hexagonal wurtzite structure. Transmittance measurements showed that the addition of Tm reduced the optical transmittance from 80% to about 50% in the visible region while the optical band gap increased slightly with Tm doping concentration. Photoluminescence spectra were dominated by an emission band due to the radiative recombination of excitons, which decreased and shifted toward lower wavelength region after Tm doping. Electrical resistivity value around 4 10-2 Ω.cm was achieved for NTZO films.

Authors : Seonkyoung Lim1, Chaewoong Kim1, Young-Man Kim2, Young-Man Kim 1,*
Affiliations : 1Applied Optics & Energy R&BD Group, Korea Institute of Industrial Technology Gwangju 500-480, Republic of Korea ; 2 Department of Material Science and Engineering, Chonnam National University Gwangju 500-757, Republic of Korea

Resume : The preparation method for the Cu(In,Ga)Se2 (CIGS) thin film solar cells absorber have been one-step or multiple-step sputtering, co-evaporation, electro deposition, electron beam deposition etc. Especially, the sputtering method is considered as a technique for CIGS-based solar cells because it can produce a commercially available thin film having a large area. The selenization process has been frequently used to crystallize of absorber layer and improve quality of the solar cells. But selenization process has been some restrictions for commercial approaches. For this reason, as one of new crystallization methods, linear type of electron beam irradiation (EBI) with excellent advantages such as minimization of composition change, fast process time and lower process temperature was introduced to our works. In this study, we have prepared a multi-layer structure containing the target with Se at the time of forming the precursor.Electron beam irradiation (EBI) system of DC power for acceleration of electron has controlled range from 1.5 to 3.5 keV, fixed 200W of RF power and 300sec of irradiation time. We have confirmed the effects of EBI on improvement of crystallization at 3keV according to SEM and XRD data. Moreover we could confirm CIGS ratio was almost unchanged by XRF data. Our results showed that EBI can be a good candidate for fast crystallization of CIGS absorber, proper to various applications such as flexible devices and easily approachable adjustment of unit.

Authors : Min-Wook Oh, J. H. Son, B. Ryu, J. E. Lee, S. J. Joo, B. S. Kim, S. D. Park, B. K. Min, H. W. Lee
Affiliations : Hanbat National University;Korea Electrotechnology Research Institute

Resume : Bismuth telluride (Bi2Te3)-based compounds have been widely used for room temperature applications in thermoelectric technologies. Both carrier concentration optimization and reducing lattice thermal conductivity is key technologies to expand the utilization of the materials. In this research, we will present the physical properties, such as band structure and defect characteristics of Bi2Te3-related compounds. The understanding of anisotropic transport properties and defects characteristics could give the direction of experiment to tune and enhance the thermoelectric properties of the compounds. For examples, a repress procedure was applied to control the anisotropic transport properties of the compounds, resulting in the enhanced thermoelectric properties in the grain-aligned samples. A high energy ball milling process was also applied to achieve carrier concentration control and reducing lattice thermal conductivity at the same time. We found the dissimilarity between p-and n-type compounds whose carrier concentrations and lattice thermal conductivity were controlled by ball milling time. Our findings suggest that optimization of carrier concentration should be considered in the high-energy ball milling process, in which reductions in grain size are expected to improve thermoelectric properties

Authors : Abdullah Alhuthali
Affiliations : Department of Physics, Taif University, P.O. Box 888, Post Code: 21974, Taif, Saudi Arabia - Email:; Tel: 966127272020, ext.: 1964; Fax: 966127256500

Resume : With the increasing of worldwide societal awareness about environmental impact, sustainability and renewable energy sources, the polymer natural fibre composites recently have attracted the attention of researchers due to the fact that they are recyclable and biodegradable. This study conducted a new infiltration method that involved very thin sheets of recycled cellulose fibres being fully soaked in viny ester resin for the development of natural fibre reinforced polymer composites. The effect of prolonged water absorption on the mechanical behaviour of cellulose fibre (0 -50 wt%) reinforced vinyl-ester composites was investigated. The elastic modulus of these composites was measured and the data were validated with various mathematical models. Exposure of these composites to water absorption for a long period of time caused a reduction in mechanical properties such as elastic modulus, strength and toughness.

Authors : Sun-Dong Kim, Hyun-Jong Choi, Young-Hm Na, Doo-Won Seo, Sang-Kuk Woo
Affiliations : Korea Institute of Energy Research

Resume : The bilayer GDC/YSZ with thin GDC diffusion barriers have been researched as SOECs and IT-SOFCs electrolytes for incorporating Co-Fe based perovskite materials which have higher electric conductivity and oxygen permeability. The drawback of Co-Fe based perovskite materials is the side reaction with the YSZ electrolyte at high temperature to form intermediates. The formation of these impurity phases increase the ohmic resistance of the electrolyte and, as a result, decrease the cell performances significantly. One possible solution is to employ a dense CeO2-based diffusion barrier layer between the YSZ electrolyte and the LSCF electrode. GDC sols have been synthesized by the controlled hydrolysis and condensation of cerium isopropoxide with each gadolinia doping agent to make a dense GDC diffusion barrier. The GDC diffusion barrier was fully densified by infiltration of a GDC sol into a porous GDC structure with a heat treatment at 1000 °C. The performance of a cell was highly improved from 0.60 W/cm2 to 0.92 W/cm2 at 750 °C by densification of the diffusion barrier. From the EIS results, the improved performance is mainly a result of the reduced ohmic resistance through the composite electrolyte. Finally, the degradation of a single cell with a dense GDC was controlled below 1.72%/1000 h, which was lower than that of porous GDC (7.69%/1000 h).

Authors : Seungmin Hyun1, Tae Gwang Yun1,2, Seung Min Han2, Jun-Ho Jeong1
Affiliations : 1. Nano-Mechanical Systems Research Division, Korea Institute of Machinery and Materials (KIMM), Daejeon 305-343, Republic of Korea 2. Graduate School of EEWS, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea

Resume : There has been great interesting in the technologies related to wearable electronics due to huge potential applications. For advanced wearable electronic applications, the reliable energy storage system with a function of flexibility and stretchability is one of key components. To realize functional energy storage device, reliable and stretchable conductive substrate and current collector should be developed. Among several substrate candidates, textile based substrate shows several benefits including large surface area, the mechanical flexibility and stretchability. The carbon-coated textile has also good conductivity that can eliminate the need for an alternative current collector. The textile substrate is suitable for supercapacitor with high electrochemical performance under mechanical strains. In this study, we have developed highly reliable and stretchable supercapacitor using textile based electrode. Polypyrrole, MnO2 and Single Walled Nanotube (SWNT) coated textile electrodes for supercapacitors were prepared from pure cotton. The textile electrode was fabricated by two coating processes of SWNT dipping and electroplating of MnO2 and polypyrrole. The textile based supercapacitor was assembled using Poly ethylene oxide (PEO) based gel-type electrolyte. The polypyrrole-coated CNT textile supercapacitor with MnO2 nanoparticles was evaluated for electrochemical performance and cyclic reliability. High electrochemical energy capacity up to 461 F/g was observed, while high cyclic reliability also improved, as 93.8% of energy capacity was retained over 10 000 cycles. Energy density and power density were measured to be 31.1 Wh/kg and 22.1 kW/kg, respectively. In situ measurement of the electrochemical performance change under mechanical strain shows that 98.5% capacity retention at 21% tensile strain and 96.3% capacity retention The fabricated flexible and stretchable energy storage device is suitable for wearable environments as demonstrated by mechanical tensile test and bending test results

Authors : Seok Gi Park1,2, Min Gu Kang2, Jeong In Lee2, Hee-eun Song2, Hyo Sik Chang1*
Affiliations : 1Graduate School of Energy Science and Technology, Chungnam National University ‎2Photovoltaic Laboratory, Korea Institute of Energy Research

Resume : High efficiency silicon solar cell requires textured front surface to reduce reflectance and to improve light trapping. In case of mono crystalline silicon solar cell, wet etching with alkaline solution is generally applied to texturing. However, alkali texturing method is ineffective for multi-crystalline silicon wafers due to grain boundary of random crystallographic orientation. Therefore, acid texturing method is generally used for multi-crystalline silicon wafers to reduce the surface reflectance. On the other hand, the acid textured solar cell shows low short circuit current due to high reflectivity even though open circuit voltage was improved. To reduce reflectivity of multi-crystalline silicon wafers, double texturing with combination of acid and silicon nanowire formation could be an attractive technical method. In this paper, we optimized condition of silicon nanowire fabrication according to Ag coating time and etching time. As a result, silicon wafers textured in acid solution without silicon nanowires showed 34% reflectance in 300-1200nm wavelength region and reflectance was decreased to ~10% after fabrication of silicon nanowires. Finally, we observed the surface structure by SEM and measured conversion efficiency of the completed solar cell.

Authors : S. Polivtseva, A. Katerski, E. K?rber, I. Oja Acik, A. Mere, V. Mikli, M. Krunks
Affiliations : Tallinn University of Technology, 19086 Tallinn, Ehitajate tee 5, Estonia.

Resume : SnS is an attractive absorber material for solar cells due to its direct optical bandgap of 1.35 eV and absorption coefficient higher than 104 cm-1. In this study SnS films were deposited by the chemical spray pyrolysis technique using tin chloride (SnCl2) and thiourea (SC(NH2)2) at molar ratios of Sn:S= 1:1 and 1:8 in aqueous solution. The precursor solution was sprayed onto soda-lime glass substrates at 200 ?C in air. We studied the effect of post-deposition annealing in nitrogen (N2) and in vacuum on properties of sprayed films. Post-deposition treatments were performed at 450 ?C for 60 min in both environments. Films were characterized by XRD, Raman and UV-Vis spectroscopies, SEM and EDX. Both the 1:1 and 1:8 as-deposited films grown at 200 ?C are composed of SnS as a main crystalline phase, an unknown crystalline phase is present additionally. According to XRD, annealing of 1:1 and 1:8 films in N2 resulted in SnO2 and Sn2S3 as main phases, respectively. Raman study supports the results obtained by XRD, and confirms the presence of SnS in both films. An unknown phase, present in as-deposited films was still present in trace amounts. Annealing of 1:1 and 1:8 films in vacuum resulted in Sn and SnS as main phases, respectively. Unknown phase present in as-sprayed films was not detected anymore. The 1:37 eV optical bangap of SnS film could be obtained by spray at 200 ?C using thiourea-rich spray solutions and applying post-deposition thermal treatment in vacuum at 450?C

Authors : Oleksandra Korovyanko1,2, Mykhailo Sytnyk3,4 Eric Daniel Glowacki1, Wolfgang Heiss3,4, Philipp Stadler1
Affiliations : 1 Linz Institute for Organic Solar Cells (LIOS), Physical Chemistry, Johannes Kepler University Linz, Altenberger Straße 69, 4040, Linz, Austria; 2 Chernivtsi National University, 2, Kotsyubynskogo, 58012, Chernivtsi, Ukraine; 3 Materials for Electronics and Energy Technology (i-MEET), Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 7, 91058 Erlangen, Germany; 4 Energie Campus Nürnberg (EnCN), Fürther Straße 250, 90429 Nürnberg, Germany

Resume : Lead-sulfide (PbS) nanocrystals (NCs) have demonstrated promising results in photovoltaic (PV) applications. It has stimulated an immense interest in the development of IR-active NCs, including synthesis, surface functionalization, and properties investigation. Nevertheless, an additional step of ligand-exchange is required in order to improve charge transport, which can be carried out after the film deposition by a ligand exchange. Post-deposition ligand-exchange strategies lead to a more full replacement of bulky organic ligands and to a better photoconductivity of obtained materials. Searching an appropriate ligand is of utmost importance for the optimization of applicable NC films properties. The objective of this research is to develop and characterize PbS quantum dot solids for the next generation PV technology. The optically active films are produced using PbS NCs colloids and applying solid-state ligand exchange with short conjugated ligands during film preparation. We performed complex investigations both for PbS NCs films optical properties before and after ligand exchange procedure and PV device characterization. This development of the post-synthetic ligand exchange procedure facilitates charge transport in the NC film while increasing the electronical communication between PbS NCs and reducing charge trapping states. Our results provide important insights on how to get better charge transfer and experimental control on the fabrication of efficient NC PVs.

Authors : Joonsoo Kim, Boyun Jang, Jinseok Lee, Jeongboon Koo, Jeongeum Lee
Affiliations : Korea Institute of Energy Research

Resume : Silicon nanoparticles (Si-NPs) were synthesized by atmospheric microwave plasma pyrolysis method using SiCl4 as starting materials in nitrogen (N2) plasma with various amounts of H2 gas. Characteritics and Electrochemical properties of Si-NPs synthesized in Microwave Plasma were investigated by XRD, SEM, TEM, XPS and charge/discharge cycles test. H2 gas flow rate was the key element to determine crystallinity of Si-NPs during Si-NPS synthesis in atmospheric microwave plasma pyrolysis. The initial reversible capacity of the core-shell structured Si-NPs synthesized with H2 gas was higher than 1000 mAh/g with initial coulomb efficiency (ICE) of 30 %, and the capacity retention was approximately 82.2 % after 50 cycles.

Authors : Y. Treekamol 1*, D. Lehmann1, M. Schieda2, T. Klassen1,2
Affiliations : 1 Helmut-Schmidt-Universität, Holstenhofweg 85, 22043 Hamburg, Germany. ; 2 Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Max-Planck-Str. 1, 21502 Geesthacht, Germany.

Resume : The inkjet printing fabrication process allows a fine control over coating morphology. The process parameters can be tuned for the production of microstructured printed electrodes, with enhanced surface area consequently improved photoelectrochemical performance. In this work, a series of microstructured photoelectrodes were successfully prepared with TiO2 nanoparticles by positioning and structuring single spots consisting of single coffee-ring-like structures. By adjusting compositions of the ink to enhance the coffee ring effect, we can increase surface area of the electrodes. The resulting electrodes show no overlapping between each printed spot. We further investigate the performance of these microstructure electrodes for photoactivated water splitting. The structured catalyst layers were printed on FTO-coated glass supports, from ethyl cellulose stabilized dispersions. For comparison, planar-layout electrodes of similar averaged thicknesses were also prepared by inkjet printing. After sintering at 300 °C under air atmosphere, the structural homogeneity of the coatings is maintained, as evidenced by confocal-laser-scanning and electron microscopy. Furthermore, the electrodes were characterized in photoelectrochemical cells containing 0.5 M H2SO4 as electrolyte and a platinum ring as counter electrode. Under simulated sunlight, photocurrent densities of up to 0.216 mA cm-2 at 1.2 V(SHE) were obtained for the oxygen evolution reaction. We are currently working on the optimization of the roughness and thickness of structured electrodes, in order to maximize their photocatalytic performance.

Authors : Da-Young Lee1, Jin-Won Lee1, Ye-Jin Jeon2, Seok-In Na1, Seok-Soon Kim3*
Affiliations : 1.Department of Flexible and Printed Electronics, Chonbuk National University; 2.Materials Science and Engineering, Gwangju Institute of Science and Technology; 3.Department of Nano and Chemical Engineering, Kunsan National University

Resume : Organometal halide perovskite such as methylammonium lead iodide (CH3NH3PbI3) has been intensively investigated as a potential candidate for next generation photovoltaics because of long exciton diffusion length, broad range of light absorption, good charge mobility, proper band gap, and excellent carrier transport. In particular, interest in planar heterojunction perovskite solar cells composed of indium tin oxide (ITO)/poly (3, 4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) hole transport layer (HTL)/methylammonium lead halide perovskite (e.g.,CH3NH3PbI3)/[6,6]-phenyl-C61 butyric acid methyl ester (PCBM)/metal cathode that can be fabricated by simple solution process at low temperature have attracted significant attention. Among main components, PEDOT:PSS HTL has latent problems such as high acidity and hygroscopic properties, leading to poor long-term stability. In this study, we investigated 2-D carboneous materials/polymer buffer layer to improve efficiency and stability of devices. Perovskite solar cell employing 2-D carboneous materials/polymer composite HTL achieved power conversion efficiency of over 10%. In comparison to the PEDOT:PSS based perovskite solar cell, stability in air also dramatically improved. Electrical and optical property of composite HTL as well as their effect on the performance and stability of solar cells will be discussed.

Authors : Yong-Jin Noh1, Sae-Mi Park1, You-Hyun Seo1, Eun-Su Choi1, Seok-Soon Kim2, Sung-Nam Kwon1, Seok-In Na1*
Affiliations : 1 Professional Graduate School of Flexible and Printable Electronics, Department of Flexible and Printable Electronics, Chonbuk National University, Jeonju-si, Republic of Korea; 2 Department of Nano and Chemical Engineering, Kunsan National University, Kunsan, Republic of Korea

Resume : We demonstrate that an easily accessible polyacrylonitrile (PAN) polymer can efficiently function as a novel solution-processable anode interfacial layer (AIL) to boost the device-performances of polymer:fullerene based solar cells (PSCs). The PAN thin film was simply prepared with spin-coating of a cost-efficient PAN solution dissolved in dimethylformamide on indium tin oxide (ITO), and the thin polymeric interlayer on PSC-parameters and -stability were systemically investigated. As a result, the cell-efficiency of the PSC with PAN was remarkably enhanced compared to the device using the bare ITO. Furthermore, with the PAN, we finally achieved an excellent power conversion efficiency (PCE) of 6.7% and a very high PSC stability, which constitute a highly comparable PCE and superior device life-time to conventional PSCs with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). These results demonstrate that the inexpensive solution-processed PAN polymer can be an attractive PEDOT:PSS alternative and is more powerful for achieving better cell-performances and lower cost PSC-production.

Authors : Jin-Won Lee1, Da-Young Lee1, Seok-In Na1, Seok-Soon Kim2*
Affiliations : 1;Department of Flexible and Printed Electronics, Chonbuk National University 2;Department of Nano and Chemical Engineering, Kunsan National University

Resume : Recently, solution-processable organic-inorganic hybrid perovskite planar heterojunction solar cells consisting of bi-layered organometal halide perovskite/[6,6]-phenyl C61-butyric acid methyl ester (PCBM) have emerged as the most promising next generation solar cells. Because record efficiency above 10 % has achieved during last few years, development of cost-competitive process, which is suitable to roll-to-roll based mass production, is necessary to commercialize it. Among various solution processes such as doctor blade and spray, brush painting is also very compatible process with roll-to-roll based mass production to achieve ideal coating on a variety of substrates, even on non-flat substrate. In this study, we demonstrate brush painted efficient perovskite solar cells. Optical and structural properties of brush painted perovskite active layer, determining final power conversion efficiency of solar cells, were investigated and strong effect of solvent and concentration on the performance was observed. Furthermore, to confirm the possibility of brush painting process, all brush painted perovskite solar cells fabricated by sequent brush painting of hole transport layer, perovskite active layer, and PCBM were studied.

Authors : You-Hyun Seo1, Jun-Seok Yeo2, Eun-Su Choi1, Yong-Jin Noh1, Sung-Nam Kwon1, Dong-You Kim2, Seok-In Na1*
Affiliations : 1 Professional Graduate School of Flexible and Printable Electronics, Chonbuk National University, Jeonju, Republic of Korea; 2 Heeger Center for Advanced Materials (HCAM), School of Material Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea

Resume : Recently, the interfacial layer between perovskite layer and the electrode has been significantly researched to approach high efficiency perovskite solar cells. Because the interfacial layer plays an important role in determining the device performance, in this respect both diode characteristics and charge transport performance. In this work, we demonstrate the blend system with n-type polymer and small-molecule as an electron transporting layer of highly efficient perovskite solar cells. In addition, change in the charge transport property, surface morphology, and recombination characteristic in a device that resulted from the control in the blend-layer of thickness were systematically investigated. As a result, the planar perovskite solar cells with blend system showed more enhanced cell-performance than device based on the conventional ETLs system, indicating that the use of the blend system is more desirable as an efficient ETL than the just small-molecule system.

Authors : Eun-Su Choi1, Yong-Jin Noh1, You-Hyun Seo1, Sung-Nam Kwon1, Han-Ik Joh2, Seok-In Na1*
Affiliations : 1 Professional Graduate School of Flexible and Printable Electronics, Chonbuk National University, Jeonju-si, Republic of Korea; 2 Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Wanju, Republic of Korea

Resume : Recently, organic–inorganic hybrid perovskite solar cells (PeSCs) have attracted great attention due to their high efficiencies. In PeSCs, cell-performances such as open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and power conversion efficiency (PCE) are highly affected by the properties of the interface between the active layer and the electrodes. For this reason, various interfacial materials such as metal oxides, conductive polymers, graphene oxide, and chemically converted graphene have been extensively studied. In this work, we introduce graphene-based materials as the solution-processed hole-transporting material (HTM) in PeSCs. The effects of graphene-based HTM on device performance are investigated in respect of cell efficiency, long-term stability, charge recombination and extraction. In addition, the PeSCs with graphene-based HTM showed enhanced PCE and long-term stability than PEDOT:PSS-based PeSCs.

Authors : Krunoslav Juraic (1,2), Davor Gracin (1), Milivoj Plodinec (1), Daniel Meljanac (1), Krešimir Solomon (3), Sigrid Bernstorff (4), Miran Čeh (5)
Affiliations : (1) Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (2) Institute of Inorganic Chemistry, Graz University of Technology, Graz, Austria; (3) Institute of Physic, Bijenička cesta 46, 10000 Zagreb, Croatia; (4) Elettra-Sincrotrone Trieste, SS 14, km 163.5, 34149 Trieste, Italy; (5) Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia

Resume : TiO2 is one of the most intensively investigated compounds in material science due to its essential properties. It is a wide band gap semiconductor having band-edge positions appropriate for solar cell applications and for hydrogen generation by water splitting. It is also known as a non-toxic, environment friendly, corrosion-resistant material. Nano-forms of TiO2 such as nanoparticles, nanorods, nanowires and, in particular nanotubes can be used as photo-electrode in dye sensitized solar cells. The conversion efficiency of solar cells can be significantly improved by using oriented nanorod-like materials on top of transparent conductive oxide. For this purpose we prepared TiO2 nanotube arrays by anodizing titanium thin film deposited on ZnO covered glass substrate. Initial Ti films were prepared by evaporation or magnetron sputtering. The diameter and length of the nanotubes were controlled by the parameters of anodization, mainly voltage and etching time. The structural properties of the obtained TiO2 nanotubes arrays were estimated by simultaneous small and wide angle x-ray scattering under grazing incidence geometry. The results will be also correlated to the deposition parameters and results obtained by high resolution electron microscopy, scanning electron microscopy and Raman spectroscopy. It will be also discussed a possible application in dye sensitized solar cells.

Authors : Juan Miguel López del Amo, Gurpreet Singh, Elena Gonzalo, Man Han, Frederic Aguesse, Montserrat Galcerán, Teófilo Rojo.
Affiliations : CIC Energigne, Albert Einstein 48, 0150 Miñano, Spain

Resume : The increasing world-wide energy demand and the threat of global warming are generating an urgent need in the society to move toward greener and more renewable energy sources. Low cost batteries are required in order to advance towards smart electric grids that integrate discontinuous energy flow from renewable fonts, optimizing the performance of clean energy sources. Na-ion batteries can be the key for this achievement, because of the huge availability of sodium, its low price and the similarity of both Li and Na insertion chemistries. One of the most promising materials as cathode for Na-ion batteries is the NaMO2 family of layered oxides (M = Cr, Mn, Fe, Co, Ni, and mixtures of 2-3 transition metals) because of their high capacity and structural simplicity. Most of the transition metal oxide materials undergo various structural transitions during sodiation/desodiation process and it is crucial to understand such transitions for the further development of these compounds. In the present work, ex situ solid-state Nuclear Magnetic Resonance (NMR) have been used as tool to understand such transitions and their impact on the local dynamics of Na+ in the bi-dimensional layers of this family of materials. The information obtained by solid state NMR is related to the performance of such compounds providing a useful tool to rationalize the effects of different metals and dopants on the electrochemistry. In particular, the impact of Fe2+, Mg2+, Zn2+, Ti4+, H+ and other dopants on the local structure and dynamics of Na+ in Mn containing layered oxides was followed by 23Na solid state NMR and the results are discussed in terms of structural order/disorder with a clear impact on the electrochemistry observed.

Authors : Hiroki Miura1, Masashi Kotani1, Yong-Gu Shim2 and Kazuki Wakita1
Affiliations : 1 Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016, Japan 2 Osaka Prefecture University, 1-1 Gakuencho, Naka-ku, Sakai, Osaka 599-8531, Japan

Resume : The quaternary compound Cu2ZnSnS4 (CZTS) has emerged as a candidate for thin film solar cells due to the abundance of its constituent elements, non-toxicity, optimal direct band gap (~1.5 eV), and high absorption coefficient (>104 cm-1). Till now, the best conversion efficiency achieved with CZTS solar cells is 8.4% [1]. To achieve even higher efficiency, it is necessary to grow high-quality CZTS films. Recently, we reported the fabrication of CZTS films with large grains using pulse laser deposition (PLD) [2]. However, the best films have cupper, zinc, and tin compositions of 26.63, 9.48, and 11.69%, respectively, deviating significantly from the stoichiometric composition. In this work, we investigate the compositional control of CZTS films deposited by PLD by preparing samples with the desired compositions. CZTS, ZnS, and SnS were used as source materials as it is difficult to achieve compositional control using the element forms of these materials. Details results and discussion will be presented at the conference. This work was partially supported by MEXT-supported Program for the Strategic Research Foundation at Private Universities, 2013-2017. [1] B. Shin, et al., Progress in Photovoltaics, Res. Appl. 21 (2013) 72. [2] Y. Watanabe, et al.: Physica Status Solidi c (in press).

Authors : Mikhail Dronov, Maria Kotova and Ivan Belogorohov
Affiliations : Mikhail Dronov123, Maria Kotova2 and Ivan Belogorohov3 1A.M. Prokhorov General Physics Institute, Moscow, Russian Federation 2M.V. Lomonosov Moscow State University, Moscow, Russian Federation 3Federal State Research and Design Institute of Rare Metal Industry ("Giredmet"), Moscow, Russian Federation;

Resume : We present the memory performance of devices with bistable electrical behavior based on polymer materials. We demonstrate that adding photosensitive particles to admixture allows us to control switching voltages and to observe photo-induced switching in addition to electrical one. From the properties of electrically-induced resistive switching and from the presence of light-induced switching we propose the necessity to consider crossover between to different switching mechanisms – filament formation and charge storage.

Authors : Katarzyna Sabolsky, Edward M. Sabolsky, John Christian, Jeremy Harp, John W. Zondlo
Affiliations : West Virginia University

Resume : One of the greatest challenges for any manned space mission is the amount of oxygen that is required, both for life support and as a chemical oxidant. Mars atmosphere is composed of 95 percent carbon dioxide, which could be efficiently electrolyzed to produce oxygen and carbon monoxide using a solid oxide electrolysis cell stack. Many recent works have centered on the co-electrolysis of carbon dioxide and water, but the study of direct electrolysis of pure carbon dioxide to oxygen and carbon monoxide is still limited. The objective of this work was to investigate cermet electrodes for use in solid-oxide electrolysis cells for the efficient reduction of carbon dioxide. This work includes the investigation of the optimal electrode microstructure that is required for performance stability. In this work, palladium-based powders were mixed with yttrium-stabilized zirconia and gadolinium-doped ceria to form cermet composite compositions. The cermet components were mixed at various ratios in order to alter the final pore size and electrode continuity throughout the final sintered film. The electrode compositions were screen-printed and sintered on YSZ electrolyte substrates to produce symmetrical cells for electrolysis testing. Four probe current-voltage measurements were completed in dry carbon dioxide on the symmetrically printed cells. The optimal Pd-based electrodes demonstrated oxygen production from dry carbon dioxide at higher level than previous reported SOE.

Authors : Lamprini G. Boutsika, Apostolos Enotiadis, Georgia Charalambopoulou, Theodore A. Steriotis
Affiliations : National Center for Scientific Research “Demokritos”, 15310, Ag. Paraskevi Attikis, Athens, Greece

Resume : Polymer electrolyte membrane fuel cells (PEMFCs), utilizing hydrogen as a fuel source, provide clean and efficient energy-conversion systems for automobiles, portable devices and stationary power generation. The continuous improvement of key PEMFCs components, such as membranes, is of top priority for the development of next generation systems with lower cost and increased durability/efficiency. The main aim of the present work is to enhance critical properties of polymer electrolyte membranes such as proton conductivity, water retention, thermal and mechanical properties by using nanofillers. In this context, a range of novel hybrid organic-inorganic materials have been developed, placing emphasis on the study of the effect of their surface chemistry on the proton transport pathway. Different nanocomposite membranes were synthesized through solution intercalation using different polymers, silica-based fillers and loadings. The samples were characterized by a combination of techniques (Powder X-ray Diffraction, FTIR and Raman Spectroscopy, Thermal Analysis, Scanning Electron Microscopy), while water self-diffusion coefficients were determined through Pulse Field Gradient (PFG) NMR measurements.

Authors : Tina Nestler1, William Förster2, Wolfram Münchgesang1, Stanislav Fedotov3, Charaf Cherkouk1, Stefan Braun2, Falk Meutzner1, Tilmann Leisegang1, Dirk C. Meyer1
Affiliations : 1Institute of Experimental Physics, TU Bergakademie Freiberg, Freiberg, Germany, 2Fraunhofer-Institute of Material and Beam Technology IWS, Dresden, Germany, 3Department of Chemistry, Moscow State University, Moscow, Russia

Resume : The constantly increasing demand for high-energy-density batteries as well as the shortage of lithium resources spurs the need to investigate other battery materials and concepts. Aluminum, with its theoretically high capacity and its high abundance, would be an excellent candidate. Up to the present, there are only a few reports on rechargeable Al-ion batteries due to the fact that the high valence of Al3+ places high demands on cathode intercalation materials and electrolytes. Finding suitable solid electrolytes is an even greater challenge. Solid electrolytes, however, could enable reliable on-chip power supply with outstanding volumetric energy densities for sensors and other applications. Literature reports on Al2(WO4)3 hint on ionic conductivity at least above 300 °C. Even though the bond valence sum mapping performed here suggests no ion conductivity at room temperature, this material was chosen as model system. Thin films have been prepared by pulsed laser deposition. The phase purity and morphology of thermally annealed thin films and thin films crystallized by flash-lamp annealing (FLA) are compared. For a deeper understanding of results of the FLA treatment, the temperature distribution is modeled. Pure Al2(WO4)3 thin films have been synthesized for the first time by thermal treatment of deposited multistacks derived from Al2(WO4)3- and Al2O3-targets. To evaluate the conduction mechanism of these films, temperature-dependent impedance spectroscopy measurements are discussed.

Authors : R. H. Damascena dos Passos (1,2), M. Arab (1), C. Pereira de Souza(2) and C.Leroux(1)
Affiliations : (1) Universit? de Toulon (IM2NP), Campus de La Garde - BP 20132 - 83957 LA GARDE Cedex - France (2) Universidade Federal do Rio Grande do Norte (LAMNRC), Campus Universit?rio Lagoa Nova, 59078-970 Natal/RN - Brazil

Resume : In the general framework of the development of membrane reactor, for methane gas transformation into syngas (H2 CO) using partial oxidation process, we propose tungstate materials as new hybrid system. Membrane reactor involves complex mechanism of ionic, electronic conduction and catalytic oxidation based on the charge carriers transfer. Thus conduction as well as catalytic properties has to be studied. Due to their chemical stability and the catalytic properties of the cerium, strontium-cerium tungstates are a good candidates for the CH4 conversion. The synthesis were carried out from EDTA-citrate complexation method. XRD analysis showed that the tungstates have the desired structure, exhibit good crystallization, without the formation of secondary phases, for a calcination temperature of 600?C. The TEM analysis of the grain size gives a mean crystallite size of 350 nm for the two studied materials. The catalytic reactivity of the samples was analyzed using a reactor coupled to a combined system of Fourier Transform Infrared spectrometer and Mass Spectrometer apparatus. The measurements were performed under methane-air gas flows, in the temperature range 500?C-1000?C. The catalytic activity was determined as a function of time, temperature and methane concentration. These materials have a good catalytic activity for the partial methane conversion. Electrical impedance spectroscopy under air showed a semiconducting behavior with electronic and ionic mix conductions.

Authors : Yuuki Sugano1, Keisuke Sato1, Naoki Fukata2, Kenji Hirakuri1
Affiliations : 1.Tokyo Denki University;2.National Institute for Materials Science

Resume : Currently, silicon (Si)-based solar cells have been used extensively, because of greater advantages such as high performance and high reliability. To expand the versatility and reduce the production cost of such solar cells, inorganic-organic solar cells that combine Si with conducting polymers have been developed. In the design of such solar cells, the control of reflectance and light absorption efficiency are of crucial importance for enhancing cell performances. We have fabricated the inorganic-organic solar cells consisting of micro-textured Si surface and polymers. We report herein the influence of thickness of polymers and annealing temperature on the cell performance of fabricated solar cells. The introduction of micro-textured Si structures with average height of 1μm and 0.8μm in average width in solar cells showed lower reflectance with value below 20% over a broad incident wavelength range of 550-1000 nm. The cell performances of such solar cells having a low reflectivity strongly depend on the thickness of polymers and annealing temperature. It is noteworthy that our inorganic-organic solar cells with thinner polymer thickness can be dramatically enhanced the PCE by 200℃ annealing, attaining the PCE of 6.4%. Therefore, we suggest that it is important to simultaneously tune the thickness of polymers and annealing temperature to be able to develop efficient inorganic-organic solar cells. This work was partly supported by JSPS KAKENHI Grant Number 26390105.

Authors : Nam Gyu-hyeon, Sung Gwan Hong, Sumg Bum Park, Yong-il Park,
Affiliations : Kumoh National Institute of Technology, Kumoh National Institute of Technolog, Dongguk University, Kumoh National Institute of Technolog

Resume : The Zirconium based alloy has been study to get high hydrogen permeability for substituting Palladium based hydrogen membrane. Especially, amorphous Ni64Zr36 membrane has high hydrogen permeability like Pd alloy membrane. In this study, we report a high hydrogen permeable of multilayered Ni64Zr36/ Nb / Ni64Zr36 and Ni64Zr36/ V / Ni64Zr36 structured membrane at the low temperature. In this multilayer structure, each layer has its own functionality at its own location. That is, Ni64Zr36 layer is located at the membrane surfaces for its high catalyst activity toward hydrogen, and Nb(or V) layer is located at the center of the membrane for its high hydrogen diffusivity. For examining the thickness ratio effect, each membrane has different thickness ratio of Nb(or V) to Ni64Zr36. The membranes are fabricated using DC-magnetron sputter on a porous Ni substrate and fixed membrane thickness to 2㎛. Finally, experimental observation shows that the membrane has different activation energy by Nb(V) thickness ratio to Ni64Zr36. The activation energy is declining when increase the thickness of Nb(V) layer between Ni64Zr36 layers. As this results, we found that the total membranes property varies as the Nb(V) when the Nb(V) thickness is increasing between Ni64Zr36.

Authors : Deok-hwan Yun, Sung Bum Park, Yong-il Park
Affiliations : Advanced Materials Engineering Kumoh National Institute of Technology, Department of Safety Engineering Dongguk University Gyeonju Campus, School of Materials Science and Engineering Kumoh National Institute of Technology

Resume : Pd-based alloys have been studied as hydrogen permeable membrane. However, Pd is prohibitively expensive and durability is degraded by Pd-H phase transition(α to β) as a lattice increase of about 5%, and this causes cracks in Pd. In this study, the Pd was replaced by the Ni-Zr alloy using high concentration of hydrogen and the gas permeable PDMS (Poly-dimethylsiloxne) was used as a flexible substrate. This membrane is able to obtain the complexible property of metal-polymer hybrid hydrogen permeable membrane. A hydrogen permeable membrane using the Ni-Zr/PDMS hybrid membrane was fabricated by spin coating, DC magnetron sputtering. The hydrogen permeability as function of Ni-Zr thickness were investigated at room temperature to 200°C

Authors : Gyu-hyoen Nam, Sung Gwan Hong, Sung Bum Park, Yong-Il Park
Affiliations : Kumoh National Institute of Technology, Kumoh National Institute of Technology, Dongguk University, Kumoh National Institute of Technology

Resume : The Zirconium based alloy has been study to get high hydrogen permeability for substituting Palladium based hydrogen membrane. Especially, amorphous Ni64Zr36 membrane has high hydrogen permeability like Pd alloy membrane. In this study, we report a high hydrogen permeable of multilayered Ni64Zr36/ Nb / Ni64Zr36 and Ni64Zr36/ V / Ni64Zr36 structured membrane at the low temperature. In this multilayer structure, each layer has its own functionality at its own location. That is, Ni64Zr36 layer is located at the membrane surfaces for its high catalyst activity toward hydrogen, and Nb(or V) layer is located at the center of the membrane for its high hydrogen diffusivity. For examining the thickness ratio effect, each membrane has different thickness ratio of Nb(or V) to Ni64Zr36. The membranes are fabricated using DC-magnetron sputter on a porous Ni substrate and fixed membrane thickness to 2㎛. Finally, experimental observation shows that the membrane has different activation energy by Nb(V) thickness ratio to Ni64Zr36. The activation energy is declining when increase the thickness of Nb(V) layer between Ni64Zr36 layers. As this results, we found that the total membranes property varies as the Nb(V) when the Nb(V) thickness is increasing between Ni64Zr36.

Authors : Christos Paterakis , Daniel Reed, David Book
Affiliations : PhD student in the University of Birmingham

Resume : School of Metallurgy and Materials, University of Birmingham, Birmingham, B15 2TT *E-mail of the corresponding author: Sodium borohydride compounds are of interest as components in materials for energy storage applications such as hydrogen storage media and solid electrolytes for ion batteries [1]. For both these applications, a greater understanding of the physicochemical properties of the borohydride compounds over a wide temperature range is required. However, to the best of our knowledge, there have not been yet any investigation of NaBH4 with bromides. Also very few calorimetric measurements have been made on the solid state phase change at low temperature. In this work, NaBH4 was ball milled with KBr. Structural and compositional characterization was performed using XRD (Bruker D8 Advance) with CuKα radiation and a Renishaw inVia Raman Microscope with a 488 nm excitation laser. The use of a DSC600 sample cell enabled DSC measurements to be performed at the same time as Raman spectroscopy between -160 ?C and 300 ?C. In addition, measurements were also made on the samples with different ball milling times (2, 4, 6, 10 and 20 hours under 1 bar argon) in order to study the effect of disorder and grain size. NaBH4 has a face-centered cubic structure (space group Fm-3m) at room temperature, but at -83 ?C it transforms into a tetragonal structure (space group P42/nmc) [2]. DSC measurements enable the estimation of the enthalpy during the solid ? solid phase change. XRD was carried out to investigate changes in structure after ball milling and preliminary analysis shows a shrinkage of the unit cell of NaBH4. References 1. Z?ttel A, Borgschulte A, Orimo S-I. Tetrahydroborates as new hydrogen storage materials. Scr Mater [Internet]. 2007 May [cited 2014 Jan 25];56(10):823?8. 2. Babanova OA, Soloninin A V, Stepanov AP, Skripov A V, Filinchuk Y. Structural and Dynamical Properties of NaBH 4 and KBH 4 : NMR and Synchrotron X-ray Diffraction Studies. 2010;3712?8.

Authors : Marius Treideris, Arunas Setkus, Irena Simkienė, Alfonsas Reza, Viktorija Strazdiene, Jevgenij Visniakov
Affiliations : Center for Physical Sciences and Technology, A. Goštauto 11, Vilnius LT01108, Lithuania

Resume : Silicon solar cells are the most widely manufactured due to well developed technology and comparatively low manufacturing cost. However future perspectives of such cells as independent devices and as integrated to system-on-the chip compared to new emerging materials in photovoltaic’s depends on new technological procedures and new solar cell concepts based on increasing the pn junction area. In this work we present solar cell based on the electrochemically etched nanotunnel matrix. Nanotunnel matrix for the solar cell was made by the low cost electrochemical etching method on n-type monocrystalline silicon wafers. P-n junction was formed by boron diffusion from spin-on borosilicate glasses. Front contact was made by chemically plated nickel grid and the back contact by depositing silver. Optical measurements have shown that electrochemically formed nanotunnel matrix can reduce reflectance in the visible range from the cell surface to less than 3%. Electrical measurements we carried under one sun illumination. In the present development phase, we demonstrate solar cell with electrochemically etched nanotunnel matrix on n-type silicon without the passivating layer with the open circuit voltage ~0.6V, short circuit current ~10 mA/cm2 and the fill factor ~0.6.

Authors : Yu-Jung Cha*, Gil Jun Lee, Yu Lim Lee, Seung Kyu Oh, Joon Seop Kwak
Affiliations : Department of printed electronics Engineering , Sunchon National University

Resume : Thermoelectric device is attended as the solutions of Energy crisis and environment deterioration. The materials of compounds containing of tellurium and antimony have the best thermoelectric properties. However, they are low friendly environment and unstable at high temperature. The oxide materials is good candidate for substitute that. Especially, calcium cobalt oxides (Ca3Co4O9) have greatly stable and good thermoelectric properties at high temperature. To the Ca3Co4O9 having good thermoelectric properties, they need sintering process necessarily. Generally, sintering process had been many method such as pulse electric-current sintering, spark plasma sintering, hot press sintering, etc,. Most methods need long time and completely process. Thus, the Ca3Co4O9 thin films were prepared by sintering with rapid thermal annealing which need short time and simple process. We measured and analyzed the thermal properties and electrical properties and changes of the Ca3Co4O9 structure by XRD, SEM, Raman spectra and hall measurement system. The Ca3Co4O9 structure was changed over 800 oC. Consequentially, we can identify that variation of structure is lead to change of electrical and thermal properties in Ca3Co4O9 thin films.

Authors : S.-J. Joo, B.S. Kim, B.-K. Min, J.-E. Lee, B.K. Ryu, H.W. Lee, S.D. Park
Affiliations : Thermoelectric Conversion Research Center, Korea Electrotechnology Research Institute

Resume : In this study, Bi2Te3 and Sb2Te3 thin films were deposited by using an RF magnetron co-sputter, and the relationship between the process parameters and the thermoelectric properties were investigated. Oxidized silicon wafers as well as thin polyimide films (thickness=25 μm) were used as substrates, and the deposition temperature was varied in the range of 200 and 350 ℃. The maximum Seebeck coefficient of the stoichiometric Bi2Te3 films was about -193 μV/K, and a power factor (PF) of 0.97 mW/mK^2 (at 32 ℃) was obtained at the optimum deposition condition. Also, the PF increases significantly when (00L) is the preferred orientation. In case of Sb2Te3, the maximum PF of 1.34 mW/mK^2 (at 98 ℃) was obtained from the nearly stoichiometric as-deposited film, which increases to 2.03 mW/mK^2 after post-deposition annealing at 350 ℃. (00L) peaks get stronger after annealing; confirming again that (00L) preferred orientation accompanies the enhancement of thermoelectric properties. The flexibility of the Bi2Te3 films deposited on the polyimide films were tested by repeatedly winding and releasing them around the metal cylinders with specific radii, and the electrical resistance was monitored with respect to the number of bending. Noticeable increase of the film resistance was not observed when the radius of the metal cylinder was larger than 5 mm, and the resistance was only 7.5 % higher than the initial value after bending 300 times using a cylinder with 5 mm radius.

Authors : Min Yi Kim, Hyo Sik Chang
Affiliations : Graduate school of Energy Science and Technology, Chungnam National University

Resume : The stress induced lift-off method is one of fabricating kerfless silicon wafer to reduce the material losses caused by the sawing of the silicon ingot. We investigate the possibility to induce the lift-off silicon foil by means of curing an epoxy resin layer on top of a (100) silicon wafer. This epoxy-induced process has the advantages of reducing metal contamination and lowers the operating temperatures below 150℃. In order to further investigate the quality of solar cell performance, we passivate the samples with ALD-Al2O3/PECVD-SiON stack layer. And then, we measure the effective carrier lifetime of exfoliated Si foils by quasi-steady-state photoconductance (QSSPC). In addition, PL image is used to detect defects of a silicon foils with high-speed and high spatial resolution.

Authors : Michael E. A. Warwick,1 Davide Barreca,2 Elza Bontempi,3 Giorgio Carraro,1 Alberto Gasparotto,1 Chiara Maccato,1 Kimmo Kaunisto,1,4 Cinzia Sada,5 Yakup Gönüllü,6 and Sanjay Mathur6
Affiliations : 1) Department of Chemistry, Padova University and INSTM, 35131 Padova, Italy.; 2) CNR-IENI and INSTM, Department of Chemistry, Padova University, 35131 Padova, Italy.; 3) Chemistry for Technologies Laboratory, University of Brescia, 25123 Brescia, Italy.; 4) Department of Chemistry and Bioengineering, Tampere University of Technology, 33101 Tampere, Finland.; 5) Department of Physics and Astronomy, Padova University, 35131 Padova, Italy. 6) Department of Chemistry, Chair of Inorganic and Materials Chemistry, Cologne University, 50939 Cologne, Germany.

Resume : High purity Pt/ α-Fe₂O₃ nanocomposites were developed through an original preparation strategy, consisting in the plasma enhanced-chemical vapor deposition of α-Fe₂O₃ (hematite) on conductive glass substrates, followed by Radio Frequency sputtering of platinum, and ex-situ annealing in air before and/or after functionalization with Pt. The data obtained by an extensive characterization through complementary spectroscopic/microscopic techniques reveal that variations of the thermal treatment procedure enable a fine control of Fe₂O₃ nano-organization, as well as of Pt redox chemistry. In particular, depending on the adopted processing conditions, annealing promoted an increase of hematite porosity/crystallinity, as well as of light absorption properties, and/or the partial reduction of Pt(II)/Pt(IV) species to Pt(0). The synergistic combination of such effects allowed to tailor material performances in photoelectrochemical H₂O splitting activated by solar radiation, yielding photocurrents as high as 638 µA cm-1 at 1.23 V vs. the reversible hydrogen electrode. The improvement of performances with respect to bare iron oxide are presented and critically discussed in relation to material structure, composition and morphology, with an eye on the dynamics of photogenerated charge carriers, investigated by transient absorption spectroscopy. M.E.A. Warwick et al., Phys. Chem. Chem. Phys., 2015, 17, 12899. M.E.A. Warwick et al., Surf. Sci. Spectra, 2015, in press, DOI 10.1116/11.20150

Authors : E. Napolitano*,1, L. Fernández Albanesi2, F.C. Gennari2, M. Hoelzel3, S. Garroni4, P. Moretto1, S. Enzo4
Affiliations : 1 European Commission -DG JRC-Institute for Energy and Transport, Westerduinweg 3, NL-1755 Petten, The Netherlands. 2 Centro Atómico Bariloche (CNEA) and CONICET, (8400) San Carlos de Bariloche, Argentina. 3 Forschungs Neutronenquelle Heinz Maier-Leibnitz (FRM II),Technische Universität München, Lichtenbergstrasse 1, D-85747 Garching, Germany. 4 Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari and INSTM, Via Vienna 2, I-07100 Sassari, Italy.

Resume : In the field of solid-state hydrogen storage, the alkali amides and alkaline-earth analogues present promising hydrogen mass and volume ratios together with remarkable reversibility in terms of hydrogen release and up-take processes [1]. Unfortunately, the formation of new unclassified phases during intermediate steps of the absorption/desorption reaction pathways may constitute a severe limitation to understanding the basic mechanisms of the reaction kinetics. Recently, with the intent to improve sorption characteristics and to modify thermodynamic properties of the well-known LiNH2-LiH system, a study on AlCl3-doped composite describing the formation of a new Li-Al-N-H-Cl compound was reported in literature [2], without its crystal structure being established. In order to elucidate the reaction pathways in complex hydrogen storage materials, the new Li-Al-N-H-Cl composite was synthesized from deuterated precursors and neutron plus laboratory X-ray diffraction data were combined with the so called ab-initio numerical methods [3] also supplemented by FT-IR, DSC and TPD-MS experimental data with the objective to solve the crystal structure and to shed light on the hydrogen atom interactions. References [1] P. Chen, et al., Nature 420 (2002) 302. [2] Fernández Albanesi et al., Int. J. Hydrogen Energy 38 (2013) 12325-12334. [3] R. Cerný, Zeit. Kristall. - Cryst Mat. 223 (2008) 607-616.

Authors : S. Kovacova1 2, J. Kovac1 2, M. Parchine1, M. Weis2, M. Donoval2, M. Bardosova1
Affiliations : 1,Tyndall National Institute, Lee Maltings, Cork City, Cork, Ireland;2 Institute of Electronics and Photonics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology in Bratislava, Ilkovičova 3, 812 19 Bratislava, Slovak Republic

Resume : There are several ways for fabrication of organic photovoltaic cells (OPV). We present OPVs fabricated using printing method (roll to roll slot-die systems),which was carried out on polyethylene terephthalate film (PET). OPV prepared on glass by spin coating method was used as a reference for the experiments. All the substratesin this work were coated by ITO used as transparent electrode with resistivity of 60 Ω sq.PEDOT:PSS (Clevios PH 1000, 1.1 % solid content in water with PEDOT:PSS ratio 1:2.5) was used as carrier injection layer. As electron donor material a poly(3-hexylthiophene) (P3HT) was used and as electron acceptor material a [6,6] phenyl C61 butyric acid methyl ester and chlorobenzene (99,8%) were used in the 20mg/20mg/1ml content.Thermally evaporated 100 nm aluminium electrode was deposited as final layer which also defined the active area with a cell size of 12-20 mm2. Light curable epoxy suitable for organic solar cells and LED encapsulation has been usedin combination with a glass cover which provides a robust barrier against ingress of oxygen and water to extended lifetime for measurement and storage.Power conversion efficiency of 0.48% has been measured for the resulting devices on plastic foil and 1.52% on reference glass sampleunder AM1.5 illumination.

Authors : S. Vatavu, N. von Morze, S. Wiesner, V. Hinrichs, M.-Ch. Lux-Steiner, and M. Rusu
Affiliations : Institut für Heterogene Materialsysteme, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, Berlin, 14109, Germany

Resume : In this contribution, CuInSe2-nanocrystals (CuInSe2-NCs) are investigated for application in hybrid organic/inorganic solar cell devices. We report CuInSe2-NCs prepared by chemical close-spaced vapor transport (CCSVT) at 450C from precursors of Cu-nanoparticles on Mo/Na barrier/glass substrates. Cu-nanoparticles were prepared by the spray ion layer gas reaction (spray-ILGAR) method at 430C. The linear dimensions and spacing of Cu nanoparticles were controlled by the substrate temperature, deposition time, flow rate and molar concentration of the sprayed ethanol solution of Cu(hfac)2. The average diameter and height of Cu nanoparticles varied depending on the deposition time as 40-60 nm and 30-80 nm, respectively. The resulting CuInSe2 nanostructures had thickness in the range of 30-170 nm. The elemental composition of the as-prepared CuInSe2-nanostructures were analyzed by Inductively Coupled Plasma Mass-Spectrometry (ICP-MS), while the phase composition was investigated by grazing incidence X-ray diffraction (GI-XRD). Stoichiometric composition was revealed by ICP-MS for optimum deposition conditions. GI-XRD (0.1-1.1 deg.) revealed diffraction peaks from (112), (204)/(220) and (116)/(332) planes of CuInSe2. Formation of (111) Cu2-xSe or (006) InSe phases were suppressed for optimum preparation conditions.

Authors : Victor Timoshenko (1,2), Kairola Sekerbayev (3), Gulden Botantayeva (3), Dana Yermukhamed (3), Yerzhan Taurbaev (3), Tokhtar Taurbaev (3)
Affiliations : (1) Physics Department of Lomonosov Moscow State University, Moscow, Russia. (2) National Research Tomsk State University, Lenina Avenue 36, Tomsk 634050, Russia; (3) Physico-Technical Department of al-Farabi Kazakh National University, Almaty, Kazakhstan.

Resume : We report results of the photoluminescence and Raman spectroscopy of thin films of organometal perovskites, which are now attracting a great attention of the photovoltaic community. The films of organometal halides are deposited by spin coating from solutions or by evaporation in vacuum conditions on quartz and glass substrates covered with fluorine-doped tin oxides and titanium dioxide. The prepared perovskite thin films are investigated by means of the electron microscopy and optical spectroscopy. Characteristics of the prepared perovskite solar cells with different parameters of the structure and composition are studied by using photoelectrical measurements. The formed perovskite solar cells are tested to reveal dependences of the conversion efficiency and stability on the preparation conditions. The obtained results are used to find the optimal structural and optoelectronic properties of perovskite thin films for creation of highly efficient solar cells.

Authors : Luyuan Paul Wang 1,2,3; Madhavi Srinivasan 1,2; Zhichuan J. Xu 1,2
Affiliations : 1. School of Materials Science and Engineering, Nanyang Technological University, Singapore 2. Energy Research Institute @ NTU, ERI@N, Interdisciplinary Graduate School, Nanyang Technological University, Singapore 3, CEA, IRAMIS, UMR 3685 NIMBE, F-91191, Gif sur Yvette, France

Resume : Hybrid electrochemical capacitors (HECs) are capable of storing more energy than supercapacitors while providing more power compared to Lithium-ion batteries (LIBs). The development of Li-intercalating materials is critical to organic electrolyte based HECs, which generally give larger potential output than aqueous electrolyte based HECs. We report a simple binder-free Nb2O5@graphene composite that exhibited excellent HEC performance as compared with other Li intercalating electrode materials. The composite exhibited enhanced cyclability with a capacity retention of 91.2% compared to 74.4% of the pure Nb2O5 half-cell when tested at a rate of 2000 mA g-1 (10 C). The composite displayed lower polarization effect when cycled at increasing scan rates (1-10 mv s-1). The enhanced rate capability could be ascribed to the use of highly conductive graphene support. As a result, the HEC composed of the Nb2O5@graphene composite and activated carbon (AC) delivered a maximum energy and power density of 29 Wh kg-1 and 2.9 kW kg-1. The performance is better than most reported HECs with other Li-intercalating electrode materials.

Authors : Maciej Kwiatkowski, Igor Bezverkhyy, Magdalena Skompska
Affiliations : Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex; Laboratory of Electrochemistry, Faculty of Chemistry, University of Warsaw, Pasteur 1 Street, 02-093Warsaw, Poland

Resume : Preparation of composite materials in the form of core-shell structures for photovoltaic, photocatalytic purposes still attracts a great attention over the years after the first successful application. Composite materials are often fabricated by deposition techniques which face the high-cost drawbacks. One of the alternative routes of preparation of ZnO/TiO2 composites overcoming this problem is to use a sol-gel method which provides simplicity and low-costs. In this report we present the results on synthesis of ZnO/TiO2 core-shell composites and their characterization by various physicochemical methods - SEM, TEM, EDX, TG-DSC, XRD, XPS, UV-Vis. Photocatalytic properties of the ZnO/TiO2 systems were determined in decolorization of methylene blue and methyl orange upon irradiation of monochromatic light of 400 nm. The ZnO nanorods were hydrothermally grown on ITO surface and covered with TiO2 layers in a simple sol-gel precipitation/deposition process. The influence of several parameters such as the TiO2 deposition time, repetition of a single deposition cycle, or/and different time and calcination temperature on the properties of the resultant systems were investigated. Diffuse reflectance spectra showed that formation of the ZnO/TiO2 interface may lead to higher light absorption in the visible range. Different morphology and thickness of TiO2 layers and formation of void spaces at the ZnO/TiO2 interface were correlated with photocatalytic activity of the samples.

Authors : M. S. Islam, G. S. Rao, T. Hussain and Rajeev Ahuja
Affiliations : Condensed Matter Theory Group, Department of Physics and Astronomy, Box 516, Uppsala University, S-75120 Uppsala, Sweden

Resume : Owing to its highest energy density per mass, the potential of hydrogen (H2) as energy carrier has been immense, however its storage remained to be a big obstacle [1]. By means of density functional theory (DFT) in spin polarized generalized gradient approximation (GGA), we have investigated the structural, electronic and hydrogen storage properties of light metals functionalized fluorographene monolayer [2]. The light metals considered here include Li, Na, Be, Mg and Al. All of these metal adatoms bind to the fluorographene with reasonable high binding energy, much higher than their cohesive energies, which help to achieve the uniform distribution of metal adatoms on the monolayer and consequently the reversibility. Each metal adatom transfer a significant amount of their charge to the fluorographene monolayer and attain a partial positive state, this facilitate the adsorption of multiple H2 molecules around the adatoms by electrostatic as well as van der Waals interaction. To get a better description of H2 adsorption energies with the metal doped systems, we have also performed the calculations using van der Waals corrections [3]. For all the functionalized systems, the results indicate a significantly high H2 storage capacity with the H2 adsorption energies fall into the range for the practical applications. References: 1. L. Schlapbach, Nature 460, 809 (2009) 2. R. R. Nair, W. C. Ren, R. Jalil et

Authors : A. Iakovleva1, M. Ben Hassine1, P. Haghi Ashtiani2, T. Reiss2, G. Dezanneau1
Affiliations : 1 Laboratoire Structures, Propri?t?s et Mod?lisation des Solides, CentraleSupelec, CNRS, Universit? Paris-Saclay, Grande voie des vignes 92925 CHATENAY-MALABRY CEDEX 2. Laboratoire M?caniques des Sols, Structures, Mat?riaux, CentraleSupelec, CNRS, Universit? Paris-Saclay, Grande voie des vignes 92925 CHATENAY-MALABRY CEDEX

Resume : We present here the study Ba2Y1 xNb1-xO6-δ (x = 0, 0.05, 0.1, 0.15, 0.2, 0.25) compounds with potential application as ion-conducting materials in Solid Oxide Fuel Cells and/or Proton Conducting Fuel Cells. Yttrium is used here as an acceptor-doping element in substitution to niobium to create oxygen vacancies by charge compensation. Nanopowders have been prepared by a freeze-drying route and dense ceramics were obtained after shaping and treatment at high temperature. X-ray diffraction analysis shows that single phase compounds are obtained for x values equal or below 0.2. Transport properties indicate that, in spite of a significant concentration of oxygen vacancies, the ion conductivity remains low in oxidative atmosphere. A higher conductivity is observed in humidified hydrogen showing that the material gets partially reduced in such conditions. Nanoscale characterization through Transmission Electron Microscopy and Molecular Dynamics calculations give further insight into the mechanisms of ion conduction and cation ordering. We show in particular that the substituting yttrium cation acts as a trap for oxygen vacancies impeding the development of high conduction level.

Start atSubject View AllNum.
Authors : Francois Aguey-Zinsou
Affiliations : MERLin, School of Chemical Engineering, The University of New South Wales, Sydney, Australia

Resume : Storing hydrogen in materials is based on the observation that metals can reversibly absorb hydrogen. However practical application of such a finding has found to be rather challenging especially for vehicular applications. The ideal material should reversibly store a significant amount of hydrogen under moderate conditions of pressures and temperatures. To date, such a material does not exist and the high expectations of achieving the scientific discovery of a suitable material simultaneously with engineering innovations are out of reach. Of course, major breakthroughs have been achieved in the field, but the most promising materials still bind hydrogen too strongly and often suffer from poor hydrogen kinetics and/or lack of reversibility. Clearly, new approaches have to be explored, and the knowledge gained with high-energy ball milling needs to be exploited, i.e. particle size does matter! The properties of nanomaterials are known to be size depend. Such size depend effect could offer powerful means to finally control both the thermodynamic and kinetic properties of hydride materials at the molecular level. Here, the potential of this new approach and the major breakthroughs we have achieved in recent years through nanosizing will be discussed. In particular, the effects of particle size restriction on some of the most promising hydrogen storage light materials, e.g. magnesium, lithium, aluminum, and borohydrides will be reported.

Authors : Jeha Kim, Yong-Duck Chung, Dae-Hyung Cho
Affiliations : Cheongju University; ETRI; ETRI

Resume : We studied the CIGS film growth incorporated with Na by using NaF evaporation in which Na ions from the soda-lime glass substrate were controlled by a presence or an absence of a SiOx barrier. Gradually increasing Na content in CIGS was found in the structures of CIGS/Mo/SiOx/SLG, CIGS/Mo/SLG, CIGS/5 nm-NaF/Mo/SiOx/SLG, CIGS/5 nm-NaF/Mo/SLG, CIGS/15 nm-NaF/Mo/SiOx/SLG, and CIGS/15 nm-NaF/Mo/SLG. With increasing Na content, the CIGS film exhibited (112) preferential growth along the surface normal with the (220/204) textures. The sample with a CIGS/5 nm-NaF/Mo/SiOx/SLG structure achieved the comparable (112)/(220/204) peak ratios, grain sizes, as well as the cell performances to a CIGS/Mo/SLG structure that contains the same Na content in the CIGS. Using the X-ray diffraction (XRD) techniques of high resolution θ-2θ scan and reciprocal space mapping, we discerned the (220)- and (204)-oriented textures of CIGS that independently depended on both substrate nature and Na presence. For a solar cell fabricated in a structure of ITO/i-ZnO/CdS/CIGS/Mo/SiOx/soda-lime glass (SLG), we found that the energy conversion efficiency η increased for relatively low Na content but the thick NaF led to a degradation of η because of poor adhesion between the CIGS and the Mo. It was observed that the hole concentration of CIGS was enhanced as the Na content increased, while the band-gap was nearly constant, which led to a lower Fermi level in the CIGS towards its valence-band edge. The Na-induced increment in the built-in potential (Vbi) across the n-(ITO/i-ZnO/CdS)/p-CIGS junction yielded an increment of open-circuit voltage that well agreed with the calculated Vbi.

Authors : Boyun Jang, Chanhi Moon, Sunho Choi, Joonsoo Kim
Affiliations : Korea institute of energy research

Resume : Wafer charges on more than 30 % of production cost for single crystalline silicon (Si) solar cells. Multiwire with free-abrasive (slurry on wire) or fixed-abrasive (diamond on wire) are usually used for slicing Si brick. Both of them, however, are based on mechanical fracture of Si by abrasive, which causes wafer breakage during the slicing and physical defects such as saw marks and micro-cracks on the sliced wafer. Therefore, slicing using multiwire without mechanical fracture of Si has a competitive potential as a new wafering process. Electrical discharge (ED) is an excellent energy source to slice Si brick because there is no mechanical stress between wire and Si. Electrical discharge is well known for precise machining of metal. We have developed pulsed-direct current (DC) ED source to slice Si brick. Single crystalline Si brick (1.65 ~ 1.72 ohm•cm) with dimension of 25 x 25 mm2 was sliced by pulsed-DC ED on 3-wires of Zn-coated Brass. Slicing speed was 20 mm2/min, which indicated that 156 x 156 mm2 wafers could be obtained only for 1,216 mins. The wafer thickness and kerf were 180 and 100 um, respectively. Details of new wafering process and wafer properties including microstructures will be presented. Some wafer samples will be exhibited as well.

Authors : Yang Doo Kim, Ju-Hyeon Shin, Hak-Jong Choi and Heon Lee
Affiliations : 1Department of Materials Science and Engineering, Korea University

Resume : One of solar cells, organic photovoltaics (OPVs) have advantages which are more cost-effective by capability of solution process, and possibly applied to various area such as portable or wearable devices due to light weight and compatibility with flexible substrates. The performance of organic photovoltaics was enhanced by many research groups. However, efficiency of organic photovoltaics (OPV), is still low. Conversion efficiency of OPV is low due to insufficient light absorption by surface reflection, simple light path in absorption layer. Efficiency of OPVs can be dramatically enhanced by light management. In this study, we used a direct printing method with poly-dimethyl siloxane (PDMS) mold to fabricate these patterned OPV. These patterns were transferred from PDMS to the active layer of OPV. This method can be performed with low cost and simple process compare to optic based lithography. After forming these patterns on the outside of the glass substrate, Conductive polymer layer and the active layer was formed using spin-coating and cathode was deposited by thermal evaporator. The conversion efficiency of the solar cells with these patterns was increased up to 7.7% in comparison.

10:30 Coffee break    
Authors : Aliaksandr S. Bandarenka
Affiliations : Energy Conversion and Storage - ECS, Physik-Department, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany

Resume : Electrocatalysis will play increasingly important role to overcome challenges associated with efficient generation and conversion of so-called “solar fuels”. The use of model electrodes, particularly single crystals, represents a good opportunity to better understand the performance of nanostructured catalytic materials: identify active sites, elucidate factors responsible for selectivity and stability of the catalytic centers. The common way of improving the activity of e.g. metal electodes is a modification of the electronic properties of the surface through alloying it with other metals. One can distinguish approaches which are based on “bulk”, “sub-surface” and “surface” alloying. Additionally, introduction of specific (often quasi-periodic) defects can also result in a drastic increase in the catalyst activity. In the presentation, examples will be given of how the above-mentioned approaches can be used to design active surfaces; and how the model electrodes can help in better understanding of the performance of “real-world” electrocatalytic systems.

Authors : G. Wang1, R. van den Berg1, K.P. de Jong1, C. de Mello Donega2, P.E. de Jongh1*
Affiliations : 1 Inorganic Chemistry and Catalysis; and 2 Condensed Matter and Interfaces Debye Institute for Nanomaterials Science, Utrecht University, The Netherlands *

Resume : Cu2O is a p-type semiconductor with a band gap of ~2.2 eV which attracts much attention for application in photovoltaics, photocatalysis and solar water splitting, but is not intrinsically stable under illumination in aqueous solutions. Cu2-xS compounds have a much higher intrinsic stability, and fascinating, though not completely understood, optoelectronic properties. However, synthesis of particles with well-defined size and morphology is a great challenge. We explore new strategies to assemble Cu-based semiconductor nanoparticles with controlled size and morphology, amongst others using mesoporous silica supports.1,2,3 For instance the size of Cu2O nanoparticles was tuned from 2 nm to 16 nm by varying either the concentration of the Cu-precursor or the pore diameter of the supporting silica, followed by subsequent conversion to Cu2O by gas-phase reduction with carbon monoxide.3 The activity, stability and selectivity of the as-obtained nanoparticles, for different sizes and compositions, were examined for solar-driven H2 evolution and in photocatalytic oxidation. A few examples will be highlighted, such as the relatively high stability of silica-supported Cu2O nanoparticles, and the possibility to influence the selectivity of the photocatalyzed oxidation reactions. Acknowledgement: The research is funded by the Dutch NRSCC-Solar Fuels program. References: 1 G. Prieto, P.E. de Jongh et al. Nature Mater. 12 (2013) 34-39. 2 W. van der Stam, C. de Mello Donega et al. Chem. Mater. 27 (2015) 283-291. 3 G. Wang et al. Submitted (2015)

Authors : Daniel Jastrzebski1, Maciej Bialoglowski1, Stanislaw Bednarz1, Edyta Pesko1, Piotr Dluzewski2, Cezariusz Jastrzebski3, Slawomir Podsiadlo1
Affiliations : 1 Faculty of Chemistry, Warsaw University of Technology; 2 Institute of Physics, Polish Academy of Sciences; 3 Faculty of Physics, Warsaw University of Technology

Resume : A vast proliferation of studies that seek novel photovoltaic materials and technologies has been observed recently. Tin(II) sulfide – a stable compound consisting of abundant and non-toxic elements – seems to be especially interesting. Owing to its electron and structural properties, it might become a promising material for highly efficient multi-junction solar devices. In this study, direct and indirect bandgap modifications of SnS nanopowders have been explored. The syntheses have been carried out in organic solvents, using tin salts and sulfur. The obtained materials have been characterized with X-ray powder diffraction, Raman scattering spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy and spectrophotometry UV/Vis/NIR.

Authors : A. Alberti1, I. Deretzis1, G. Pellegrino1, C. Bongiorno1, E. Smecca1, G. Mannino1, F.Giannazzo1, G. G. Condorelli2, N. Sakai3, T. Miyasaka3 , C.Spinella1 and A. La Magna1
Affiliations : 1 CNR-IMM Zona industriale, Strada VIII 5, 95121, Catania, Italy 2 Università degli Studi di Catania and INSTM UdR Catania; Viale Andrea Doria 6, 95125 Catania, Italy. 3 Toin University of Yokohama, Graduate School of Engineering, 1614 Kuroganecho, Aoba, Yokohama, 225-8503, Japan

Resume : We investigate the degradation path of methylammonium lead iodide (MAPbI3) films over flat TiO2 substrates at room temperature by means of X-Ray Diffraction, Spectroscopic Ellipsometry, X-ray Photoelectron Spectroscopy and High Resolution Transmission Electron Microscopy. We find out that the degradation dynamics is similar in air and vacuum conditions. In particular, the process has an early stage, which drives the starting tetragonal lattice in the direction of a cubic atomic arrangement, at fixed MAPbI3 stoichiometry. Such early stage is followed by a phase change with the PbI2 as the main solid product. This degradation product is structurally coupled with the original MAPbI3 lattice through the orientation of its constituent PbI6 octahedra and progressively erodes the starting MAPbI3 film. The similarity of the degradation dynamics in air and vacuum highlights the occurrence of intrinsic thermodynamic mechanisms not necessarily linked to humidity.

12:30 Lunch break    
Authors : Ying Chen, A. Saengdeejing, M. Matsuura, S. Sugimoto
Affiliations : Department of Nanomechanics, School of Engineering ,Tohoku University, Department of Materials Science, School of Engineering, Tohoku University

Resume : The Nd-Fe-B based magnets are widely used in many critical components like motors, generators, wind turbines, cell phones and hard disks, especially the automotive application is rapidly increasing in recent years. The development of advanced rera-earth permanent magnet materials with high coercivity draws much attention at the relation between coercivity and microstructure at the grain boundaries of magnets. A disordered fcc-NdOx phase formed at the interface of Nd/Nd-Fe-B is observed and it is believed to take an important role in coercivity generation 1,2). To have a thorough understanding on the formation mechanism of this particular oxide, and its relation to the surface coercivity, ground state analysis for whole oxygen concentration in Nd-O has been performed by combing the LSDA+U and the Cluster Expansion Method (CEM). Systematic calculations revealed that a sequent fcc-based structures formed by introducing oxygen vacancies into NdO is stable in almost all 0-50% oxygen concentration range, whereas in a series hcp-based structures developed from hp5-Nd2O3 no stable structure is observed3), which coincides with the experimental measurement very well. Further analysis of formation energies and relevant changes in electronic structures of single oxygen vacancy in various structures revealed the insight of such fcc-based phase formation, and further explained the relation between the phase stability and coercivity. The stability and binding properties of the Cu-doped Cu-fcc-NdOx structures which was reported to be favorite for increasing coercivity are also investigated. References 1) S. Hirosawa, T. Fukagawa and T, Maki, Phys.stat. sol (c). 4, 4606 (2007). 2) T. Fukagawa and S. Hirosawa, J. Appl. Phys.104, 013911 (2008). 3) Ying chen, A. Saengdeejing , M. Matsuura, S. Sugimoto, JOM, 66, 1133 (2014).

Authors : Yong-Mook Kang*, Kyeongse Song, Mihui Park, Jaepyeong Jung, Daniel Adjei Agyeman
Affiliations : Department of Energy & Materials Engineering, Dongguk University-Seoul, 100715 Seoul, Republic of Korea

Resume : Rechargeable lithium batteries have the potential to provide an energy storage solution to depletion of fossil fuel resources and global warming because they are also considered as clean power sources from renewable energy sources for next-generation electric applications such as electric vehicle (EV), portable electric appliances, and large-scale energy storage system. The energy density of the conventional lithium ion battery cannot meet the stringent requirements for these applications, whereas lithium-air batteries have significantly high theoretical specific energy coming up to 11,140 Wh/kg because lithium–air batteries are based on discharge reaction between Li and oxygen to yield Li2O2. However, regardless of its high energy density, low cycling capability remained as an important hurdle for commercialization. A major drawback about lithium-air batteries is its low round trip efficiency coming from very large potential difference between ORR and OER (Oxygen evolution reaction). Various types of materials have been adopted for the catalysts to reduce potential hysteresis and thus attain high round-trip efficiency. In particular, α-MnO2 has received great attention as an oxide catalyst for lithium-air batteries since its superior catalytic activity was introduced by P.G. Bruce et al.. Because the relatively good catalytic activity of α-MnO2 among various metal oxides results from easy accommodation of Li2O2 inside its large 2x2 tunnel structure, many researchers have tried to vary the macrophysical properties such as porosity, surface-to-volume ratio and so on to enhance the electrochemical properties of lithium-air batteries using α-MnO2. However, such kind of piecemeal approaches without detailed understanding on the fundamental physical properties governing the catalytic activity of materials failed to make a breakthrough in the development of commercially available catalysts. Hence, the shape or surface structure of catalysts has been regarded as the crucial physical factors to determine its catalytic activity in various applications. However, very little is known about the catalyst shape-dependent activities or the structure sensitive catalytic activities for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in the cathode of lithium-O2 battery. Hence, we here try to change the crystal structure, surface structure and shape of noble metal catalysts to elucidate their effects on the catalytic activities. Various catalysts such as PdCu, Pt3Co, Pt, etc. have been used to figure out the fundamental design principles of noble metal catalysts for Li-O2 batteries. As a result, we knew that surface energy, crystal structure and elemental composition are all important to develop the most optimum metal catalysts to attain high reversibility of Li-O2 batteries.

Authors : Davide Barreca,1 Giorgio Carraro,2 Michael E. A. Warwick,2,* Kimmo Kaunisto,2,3 Alberto Gasparotto,2 Valentina Gombac,4 Cinzia Sada,5 Stuart Turner,6 Gustaaf Van Tendeloo,6 Chiara Maccato,2 Paolo Fornasiero4
Affiliations : 1) CNR-IENI and INSTM, Department of Chemistry, Padova University, Padova, Italy.; 2) Department of Chemistry, Padova University and INSTM, 35131 Padova, Italy.; 3) Department of Chemistry and Bioengineering, Tampere University of Technology, 33101 Tampere, Finland.; 4) Department of Chemical and Pharmaceutical Sciences, ICCOM-CNR Trieste Research Unit - INSTM Research Unit, Trieste University, 34127 Trieste, Italy.; 5) Department of Physics and Astronomy, Padova University, 35131 Padova, Italy.; 6) EMAT - University of Antwerp, 2020 Antwerpen, Belgium.

Resume : Fe₂O₃-TiO₂ nanocomposites are fabricated by a vapor phase synthetic strategy involving the atomic layer deposition of TiO₂ films with variable thickness onto hematite ( α-Fe₂O₃) nanodeposits produced by plasma enhanced-chemical vapor deposition, and final annealing in air. The resulting materials are carefully characterized in their structural, compositional, morphological and optical properties by complementary characterization techniques, and their photocatalytic performances are tested in the photo-degradation of a model organic dye (Methyl Orange) in aqueous solutions, triggered by solar irradiation. The uniform coverage of Fe₂O₃ nanostructures by TiO₂ also in the inner specimen regions, allowing an intimate contact between the two oxides and a fine control on the resulting heterojunction, synergistically contributed to the improved photocatalytic behaviour with respect to bare Fe₂O₃ and bare TiO₂. The promising results presented and discussed in this work disclose potential new perspectives for application in wastewater treatment, an issue of doubtless practical significance for environmental protection.

Authors : Eylül Saraç, Uğur Ünal
Affiliations : Graduate School of Science and Engineering, Koç University, Rumelifeneri Yolu, Sarıyer, Istanbul, Turkey; Chemistry Department, Koç University, Rumelifeneri Yolu, Sarıyer, Istanbul, Turkey

Resume : Electrochemical Capacitors (ECs) are in the focus of electrical energy storage research field due to their long term stability, environmental compatibility, and high energy density without sacrificing any power density. In the study of interest, composites of graphene oxide and different metal ions (Fe, Co, Cu, Mn, Ni, and Ag) are combined to produce electrodes for ECs; the effect of reducing graphene oxide on specific capacitance (SC) is examined. Graphene obtained from reduction of graphene oxide has several advantages compared to graphene obtained from direct exfoliation of graphite. Former one has dispersibility in aqueous environment, and pseudocapacitative properties due to remaining functional groups. Composite electrodes are tested on HOPG (highly oriented pyrolytic graphite) electrodes by Cyclic voltammetry in different electrolyte solutions and in different potential ranges for different metal ions. It has been observed that there is a significant increase in SC values of composite electrodes after reduction of graphene oxide. Before reduction, maximum SC are obtained with Fe2+ and Cu2+ composites having SC of 28.3mF/cm2 and 25.8mF/cm2 at scan rate of 20mV/s, respectively. Whereas after reduction, maximum SC having samples are Co2+ and Mn2+ with 144.0mF/cm2 and 134.5mF/cm2 (at scan rate 20mV/s), respectively. Moreoever, there is almost twenty fold increase in SC in Mn2+, Co2+, and Ni2+ composites before and after reduction of samples. The reasons behind the enhanced capacitance are examined by X-ray photoelectron spectroscopy, Raman spectroscopy, and Field-Emission scanning electron microscopy by analyzing the electrodes before and after reduction of graphene oxide.

15:30 Coffee break    
Symposia A & C Joint Session : Main building, Room 134
Authors : Gour P. Das
Affiliations : Department of Materials Science, Indian Association for the Cultivation of Science, Kolkata-700032, INDIA

Resume : In search of the right material for hydrogen storage, complex hydrides involving light metals, such as Alanates, Imides, Borates, Amidoboranes etc. [1,2] show impressive gravimetric efficiencies, although the hydrogen desorption temperatures turn out to be rather high. Nanostructuring (via ball milling) is expected to improve the desorption enthalpy as well as the desorption temperature due to the higher diffusivity of hydrogen and higher surface to volume ratios of the nanoclusters [3]. Apart from hydrides, there are other kinds of novel materials that have been investigated, e.g. carbon based materials activated with nano-catalysts, metal-organic complexes, and more recently nanostructured cages viz. fullerenes, nanotubes and graphene-like 2D sheets decorated with simple or transition metals that serve to attract hydrogen in molecular form [4-6]. In this talk, I shall discuss the results of our first principles density functional theory (DFT) based investigation of the structure, stability and desorption kinetics of H2 focus on both the two above mentioned classes of materials. Some outstanding issues and challenges, like how to circumvent the problem of metal clustering on surface, or how to bring down the hydrogen desorption temperature etc. will be discussed. Finally, I shall present a comparative study of the different kinds of stable nanostructured materials with large surface area, from the point of view of their promise and practicability for hydrogen storage. [1] S. Bhattacharya et al, J. Phys. Chem. C Letter 112, 11381 (2008); J. Phys. Chem C 116, 8859 (2012). [2] S. Bhattacharya and G.P. Das, Review Article in ‘Concepts and Methods in Modern Theoretical Chemistry’, Eds. S.K .Ghosh and P.K. Chattaraj (CRC Press, 2013) pp. 415-430. [3] P. Banerjee, K.R.S. Chandrakumar and G.P. Das, communicated (2015). [4] S. Barman et al, J. Phys. Chem. C 112, 19953 (2008). [5] S. Bhattacharya et al, J. Phys. Chem. C Letter 112, 17487 (2008); Bull. Mater. Sci. 32, 353 (2009); J. Phys. Chem. C 113, 15783 (2009); J. Phys. Chem. C 116, 3840 (2012). [6] A. Bhattacharya et al, J. Phys. Chem. C 114, 10297 (2010).

Authors : Robert Johansson, Rajeev Ahuja, Olle Eriksson, Björgvin Hjörvarsson, Ralph H. Scheicher
Affiliations : Department of Physics & Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden

Resume : The site occupancy of hydrogen atoms in strained body-centered cubic vanadium is investigated using density functional theory. Predominant occupancy of either the tetrahedral or the octahedral interstitial sites results from the different effect by the strain state of the material. Interstitially absorbed hydrogen will itself give rise to local strain fields in the material. For large enough hydrogen concentrations, the sum of these local strain fields will combine to give rise to a change in volume which in turn alters the energetic landscape of the absorbed hydrogen. We predict that a change in site occupancy from tetrahedral to octahedral will occur at a critical strain at which the energetics of hydrogen site occupancy becomes equal. We also predict hysteresis behavior in the site occupancy during the loading and unloading of hydrogen in the system. This phenomenon has been experimentally observed and theoretical calculations that will be presented provide an atomistic insight to the underlying process.

Authors : Zbigniew Łodziana
Affiliations : Institute of Nuclear Physics PAN, Department of Structural Research, ul. Radzikowskiego 152, 31-342 Kraków, Poland.

Resume : Metal borohydride complexes and their derivatives are of interest due to their potential as an energy storage materials. Tuning of their thermodynamic and kinetic properties is achieved via formation of mixed-metal borohydride complexes; ammonia-containing metal borohydrides; confinement in small nanopores. Any of such procedures leads to materials with complex crystalline structure that is difficult to study due to large fraction of light elements. This complexity is a challenge for theoretical description. Challenges in theoretical description of tuned complex hydrides will be presented, and simple descriptor of their stability based on ionic potential will be introduced. Such descriptor is related to well-known relation between stability and Pauling electronegativity, however it can be accurately calculated for crystalline materials.

Authors : Didier Blanchard (1), Agata Bialy (2), Peter B. Jensen (1), Tejs Vegge (1), Ulrich J. Quaade (2)
Affiliations : 1- DTU Energy Conversion, 2800 Kgs. Lyngby, Denmark; 2- Amminex Emissions Technology A/S, Gladsaxevej 363, 2860 Soeborg, Denmark

Resume : Metal halide ammines are very attractive materials for ammonia absorption and storage1. Applications include thermochemical heat pumps2, NH3 separation3, storage4 for fuel cells5 and selective catalytic reduction of NOx from combustion processes6. However, the release of NH3 from metal halides often occurs in multiple steps and at too high temperatures for these applications. Therefore, there is a need for new materials and to search for new mixed metal halide chlorides, we use Density Functional Theory calculations, guided by a genetic algorithm to expedite the search (the defined search space contains more than 100,000 different structures). We search for materials releasing ammonia below 100 ?C. The efficiency of the implemented algorithm is verified by 3 trial runs capable of finding the same optimal mixtures starting from different random populations, testing < 5% of the candidates. Some of the best candidates are already confirmed experimentally and others offer a record high, accessible hydrogen capacity exceeding 9 wt%. Among the identified materials is the first known high-capacity ternary metal halide ammine, which has been synthesized and its NH3 storage properties using temperature programmed desorption. References 1- T. Vegge et al. Walker, G., Woodhead Publishing Ltd, Cambridge, 2008 2- E.S. Lepinasse et al. Int. J. of Refrigeration 17(1994) 309 3- C. Liu et al. Bull. Chem. Soc. Jpn. 77(2004) 123 4- C.H. Christensen et al. J. Mater. Chem. 15, 4106(2005) 4106 5- D. Chakraborty et al. Fuel Cells Bull. 12 (2009) 6- T. Elm?e et al. Chem. Eng. Sci. 61 (2006) 2618

Authors : Ali Zeaiter, David Chapelle, Philippe Nardin
Affiliations : FEMTO-ST, Department of Applied Mechanics, 24 rue de l’épitaphe 25000 Besançon France

Resume : A macro-scale thermodynamic study [1, 2] was performed in order to describe the hydriding reaction abs/des inside a cylindrical tank. To set off an absorption or desorption reaction, several type of solicitations can be applied to the tank such as: Applied Hydrogen pressure, external temperature, inlet and outlet flux. The predicted output variables attached to the hydride reaction will have a time-space profile and can be cited as follow: local temperature, local reaction rate, local equilibrium pressure, and the local heat generated or needed. Two outputs variables have the most important weight when talking about the efficiency of the hydride reaction, they are: the desorption reaction rate and the output flux. Interactions between a full cell, and a hydrogen cylindrical tank in the stage of desorption are defined by these two output variables, the impact of the non-uniformity according to time of the output flux on the full cell power was identified, in order to establish the optimum working regime of such a system. References: 1] B.A. Talaganis, G.O. Meyer, P.A. Aguirre ‘’ Modeling and simulation of absorption-desorption cyclic processes for hydrogen storage-compression using metal hydrides ‘’ International Journal of hydrogen energy 2011:36:13621-31 [2] A.Zeaiter, D.Chapelle, P. Nardin ‘’searching out the hydrogen absorption/desorption limiting reaction factors, Journal of alloys and compounds (In press)

Start atSubject View AllNum.
Authors : P. Jena
Affiliations : Virginia Commonwealth University

Resume : Complex metal hydrides and Li-ion batteries play an integral role in the pursuit of clean and sustainable energy. The former stores hydrogen and can provide a clean energy solution for the transportation industry while the latter can store energy harnessed from the sun and the wind. However, considerable materials challenges remain in both cases and research for finding solutions has traditionally followed parallel paths. I will show that there is a common link between these two seemingly disparate fields which can be unveiled by studying the electronic structure of the anions in complex metal hydrides and those in electrolytes of Li-ion batteries; they are both superhalogens [1]. I will also demonstrate that considerable progress made in our understanding of superhalogens in the past decade can provide solutions to some of the material challenges in both these areas. [1] P. Jena, ?Superhalogens-A Bridge Between Complex Hydrides and Li-ion Batteries?, J. Phys. Chem. Letters 6, 1119 (2015) (invited perspective)

Authors : Anja Bieberle-H?tter
Affiliations : DIFFER (Dutch Institute for Fundamental Energy Research)

Resume : The direct conversion of solar energy into storable fuels is a holy grail in the area of sustainable energy solutions. Photo-electrochemical solar fuel conversion is considered as a very promising route for the production of fuel from sunlight. It is believed to reach higher overall efficiencies than water splitting through an electrolyser powered by photovoltaics [1]. However, since the early studies of Fujishima et al. [2], a commercial breakthrough has not yet been achieved, mainly due to efficiency and stability issues of the photoelectrodes. Current research focuses mainly on experimental studies; modeling & simulation studies are in general rare and strongly focus on combinatorial studies in order to find alternative materials. In this presentation, we will summarize the current approaches which are taken to model the photo-electrochemical interface in order to gain a better understanding of the mechanisms taking place there. We will discuss the challenges in general and with individual approaches. Then, we will discuss our multi-scale approach of modeling & simulations of photo-electrochemical interfaces where we strive to compare experimental and simulated data directly. Experimental results on hematite model electrodes and Density Function Theory (DFT) calculations of the same surfaces will be presented. 1 van de Krol, R. & Gr?tzel, M. Photoelectrochemical Hydrogen Production (Springer, 2012). 2 Fujishima, A. & Honda, K. Nature 238, 37-38 (1972).

Authors : M. Ben Hassine1,2, C. Davoisne1,2, C. Tessier3, G. Drazic4 and L. Dupont1,2
Affiliations : 1LRCS, CNRS UMR 7314, Universit? de Picardie Jules Verne, 80039 Amiens, France. 2R?seau sur le Stockage Electrochimique de l?Energie (RS2E), FR CNRS 3459, France. 3 SAFT- 111 Bd Alfred Daney, 33074 Bordeaux Cedex. 4Laboratory for Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia.

Resume : The main objective of the ANR Vision project is to propose Li-ion batteries for energy storage application associated with renewable energy with a lifetime of 15-20 years. The scientific goal is to improve knowledge of long time aging mechanisms according to use conditions. This understanding would be helpful for improvement of prototypes that will be tested during the project. Batteries made of Li[Ni1-x-yMnxCoy]O2 (NMC) and carbon a are investigated. Electron microscopy techniques (Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), High Resolution-High Angle Annular Dark Field (HR-HAADF), Focused Ion Beam (FIB), Electron Dispersive Spectroscopy (EDS) and Electron Energy Loss Spectroscopy (EELS)), were deeply used to determine the degradation of the aged active materials: stress, strain, fracture, phase transformations, dissolution resulting from intense cycling. By comparison of pristine and cycled materials, SEM investigation on FIB electrode slices revealed detachments and cracks inside and between active material and the binder as well as preferential dissolution [1] of transition metal (EDS). SAED patterns show the creation of defects and highlight a transition phase from lamellar to spinel phase. In order to nicely visualized spinel domains [2,3], images were recorded on a JEOL ARM 200 CF Cs-corrected microscope fitted with HR-HAADF camera. Afterwards, all these results, combined with information recorded by the other VISION partners, are used to make recommendations to create new generations of prototype cells. [1] N. P. W. Pieczonka et al., J. Phys. Chem. C, 117 (2013) 15947−15957. [2] A. Boulineau et al., Chem. Mater., 24 (2012) 3558−3566. [3] D. Mohanty et al., J. of Power Sources, 229 (2013) 239-248. Acknowledgement: This work was funded by ANR (Agence Nationale de la Recherche) and is part of the VISION project.

Authors : Mehtap Ozdemir*, Sena Gulen, Seda Ulusoy, Gulnur Aygun, Lutfi Ozyuzer
Affiliations : Mehtap Ozdemir*, Sena Gulen, Seda Ulusoy, Gulnur Aygun, Lutfi Ozyuzer Department of Physics, İzmir Institute of Technology, Urla, 35430, İzmir, TURKEY *Department of Electrical and Electronics Engineering, Gediz University, Seyrek, 35650, İzmir, TURKEY

Resume : Because of its high energy, long life cycle and eco-friendly properties, the most preferred rechargeable batteries are Lithium-ion batteries. Due to having high safety and reliability, non-combustible inorganic solid electrolyte batteries will replace with the conventional liquid electrolyte lithium batteries. Having high energy density, no memory effect and slow energy losses, all solid-state rechargeable Li-ion batteries have potential applications in portable electronic devices, power source for space vehicles and electrical cars. One way of increasing these properties is to produce electrolyte as a thin film. Thin film Li-ion batteries have high specific energy and power, high energy efficiency, better performance at high temperatures and slow discharge characteristics. Therefore, in this study, we prepared a series of Al doped lithium lanthanum titanate (LLTAlO) thin film electrolytes using LLTAlO targets in a Ar atmosphere by radio frequency (RF) magnetron sputtering technique. We also deposited LLTO thin films in an Ar atmosphere under the same conditions as a reference for comparison. The morphology and the composition of the thin films were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The chemical state and atomic concentration were determined by X-ray photoelectron spectroscopy (XPS). Moreover, ionic conductivity was determined by Impedance Analyzer.

10:30 Coffee break    
Authors : N.L. Saini
Affiliations : Dipartimento di Fisica, Sapienza Universit? di Roma, P.le Aldo Moro 2, 00185 Roma, Italy

Resume : Transition metal oxides are commonly used in Li-batteries, however their peculiar physical properties can be limiting factors for the desired battery characteristics. Here, we will briefly review site-selective structural properties of LiCoO2 and V2O5 battery materials, measured by x-ray absorption spectroscopy. The nanostructuring of LiCoO2 is found to have direct effect on the bondlength characteristics, with a substantial change in the force constant of Co-O bonds while Co-Co bonds showing hardly any change. Therefore, both random disorder and Co-O bondlength flexibility should be the factors to limit the charging/discharging characteristics of the LiCoO2 nanoparticles. On the other hand, study of morphologically different V2O5 reveals distinct local structure properties as well the electronic structure. It is found that the nanowires have a significantly ordered chain structure in compare to the V2O5 bulk, having direct implication on the use of nanowires as battery materials. We have also determined local structure of LiMnO2, LiMn(1-x)Cr(x)O2 and LiMn(1-x)Ni(x)O2 compounds, showing the Jahn-Teller distortions in LiMnO2 and their suppression in substituted systems. Distinct local disorder in differently substituted LiMnO2 seems to be the reason for distinct battery characteristics of these materials.

Authors : Ozcan Ozmen, John Zondlo, Shiwoo Lee, Kirk Gerdes and Edward M. Sabolsky
Affiliations : Department of Mechanical and Aerospace Engineering, West Virginia University Morgantown, West Virginia 26506, USA; Department of Chemical Engineering, West Virginia University Morgantown, West Virginia 26506, USA; US DOE-National Energy Technology Laboratory, Morgantown, WV 26507, USA; US DOE-National Energy Technology Laboratory, Morgantown, WV 26507, USA; US DOE-National Energy Technology Laboratory, Morgantown, WV 26507, USA; Department of Mechanical and Aerospace Engineering, West Virginia University Morgantown, West Virginia 26506, USA

Resume : Nano-catalyst infiltration within the porous Solid Oxide Fuel Cell (SOFC) electrodes is a well-known method to increase electrochemical performance. In this study, an alternative process was developed to efficiently infiltrate nano-catalyst into the commercial SOFC electrodes. Mussel inspired adhesives were used as a surfactant layer within the 3-D electrode architecture to better control the infiltration kinetics and dispersion of the nano-catalyst. The work assessed the use of polymerized dopamine (PDA) and/or nor-epinephrine (PNE) as the bio-template layer for metal hydroxide deposition. The adhesive effect of the bio-template was shown to provide up to 3 times higher nano-catalyst loading by avoiding segregation of the precipitate within the porous structure. Long term (~300 hour) cell performance and the final nano-catalyst characterization was developed by voltage-current-power testing and impedance spectroscopy during the constant current loading. The protocols showed an initial increase of the maximum power density at 750C using humidifed H2 fuel up to ~20.7. However, grain growth of the nano-catalyst within the electrode caused a decrease in performance to 5.6 % at the end of 300h. AFM analysis clearly showed the time dependent growth of ceria particles at cell operating temperature. Current work focuses on the infiltration of multi component catalyst systems to hinder particle coarsening related to cell performance degradation.

Authors : G. Maino 1, S. Gielis 1, E.J. van den Ham 1, N. Peys 1,2, P.M. Vereecken 2, A. Hardy 1,2, M.K. Van Bael 1,2
Affiliations : 1. Hasselt University, Institute for Materials Research, Inorganic and Physical Chemistry and imec, division imomec, Martelarenlaan 42, 3500 Hasselt, Belgium; 2. imec, 3001-Leuven, KU-Leuven, Centre for surface chemistry and catalysis, 3001 Leuven

Resume : Li-ion batteries are known as promising candidates to overcome the energy storage problem due to their high working voltages, energy density and long life. However, contemporary planar thin film batteries could be improved significantly by increasing the surface area of the electrodes, yielding a 3D battery, which will provide high Li ion conductivity, high capacity (compared to the planar system) and high power, due to the increased surface area and short diffusion lengths1. LiMn2O4 (LMO) is an excellent candidate as cathode due to its high (4V) voltage plateau, non-toxicity and good recyclability. In this study, a spray-coating route is being explored for the LMO thin film deposition on TiN and Pt coated planar Si substrates and Si micropillars. Through an elaborated study of the precursors chemistry, deposition and processing, specific conditions are derived for the successful deposition of a crystalline, electrochemically active and stable LMO thin films in 2D and 3D. It is found that the film features depend mainly on the precursor and spray-coating parameters. The crystallinity, morphology, thickness and electrochemical properties are studied via Raman, XRD, (X-)SEM and Cyclic Voltammetry, respectively. The study yields interesting insights in the synthesis, deposition and electrochemical activity of LMO both in 2D and 3D systems, bringing a 3D all-solid state battery one step closer. 1) Adv. Mater. 2007, 19, 4564-4567

Authors : Michał A. Borysiewicz1, Marek Ekielski1, Marek Wzorek1 and Marcin Myśliwiec1,2
Affiliations : 1 Instytut Technologii Elektronowej, al. Lotników 32/46, 02-668 Warsaw, Poland; 2 Institute of Microelectronics and Optoelectronics of Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warsaw, Poland

Resume : We present the preliminary results of material studies and performance characterizations of transparent supercapacitors based on fully sputter deposited electrodes. The main electrode is a 300 nm thick nanocoral ZnO film, covered by a 10 nm thick transparent MnO2 film. The ZnO serves as a highly developed surface skeleton while the MnO2 enhances the capacitance of the device. The electrodes are fabricated on FTO-covered glass and an LiCl/poly(vinyl alcohol)-based gel electrolyte is applied. To produce a conducting material, the nanostructured ZnO was n-type doped with H. A proprietary rapid thermal annealing process was applied, utilizing an Ar/H2 atmosphere and temperatures ranging from 300°C to 500°C. The doping did not influence the film structure as evidences by SEM and X-ray diffraction studies. The phases in the MnO2 thin film were determined using selective area electron diffraction in a TEM. The supercapacitor was characterized using cyclic voltammetry in the range 0-1 V with 20-100 mV/s sweeps. The high application potential of ZnO in supercapacitors was proved by the recorded capacitances greater than 20 μF/cm2 in the majority bias range with 94% capacitance retention after 1600 charging/discharging cycles. This research was supported by the National Centre for Research and Development in the frames of the Lider V Programme through the project ‘Nanocoral zinc oxide-based supercapacitors for transparent electronics (NACZO)’, contract: LIDER/030/615/L-5/NCBR/2014.

Authors : Mylad Chamoun, Dag Noreus*
Affiliations : Department of Material and Environmental Chemistry, Stockholm University, Sweden

Resume : The inexpensive, safe and earth-abundant iron metal is a promising active material candidate for the anode in the alkaline Metal-Air battery system. The Fe anode is capable to deliver a theoretical specific capacity of 962 mAh/g with an astonishingly low raw price of $0.44/kg. Nevertheless, a feasible system has yet been proposed with good long term efficiency. Fe electrodes suffers from two major obstacles: low coulombic efficiency and passivation layer buildup upon charge-discharge cycling. Hence, conventional Fe electrodes exhibit an unsatisfactory specific capacity of ~250 mAh/g and coulombic efficiency of ~60%. Here, we demonstrate Fe electrodes with significant capacity retention over 100 cycles by the use of appropriate sulfide- and stannate-based additives. The combined additives presents a substantial increase in specific capacity (>500 mAh/g) and coulombic efficiency (>90%) in contrast to conventional Fe electrodes. We demonstrate conclusively that the use of sulfide-ions in solution forms conductive iron sulfide complexes on the surface and enhances the reversibility of the Fe electrode. Furthermore, we validate that the stannate-ions in the bulk suppresses the overpotential of H2 resulting in gas-free reduction of iron upon charging. Most promising is that the novel combination of above mentioned additives exhibits a noteworthy synergy, and may potentially be the answer for a feasible anode in the Metal-air battery system.

12:30 Lunch break    
Authors : Stuart Irvine*, Dan Lamb*, Vincent Barrioz*, Mark Baker**, Rossana Grilli**, Craig Underwood**
Affiliations : *CSER, OpTIC Centre, Glyndŵr University, St Asaph LL17 0JD, UK **Faculty of Engineering & Physical Sciences, University of Surrey, Guildford GU2 7JP, UK

Resume : Thin film photovoltaics (PV) can be deposited in one of two configurations, known as either the “substrate” or the “superstrate”. The “substrate” starts with back contact and absorber layer, finishing with the window layer and TCO where the “superstrate” starts with the window. Both can have advantages for different applications and indeed preferences for particular absorber materials where CdTe prefers a “superstrate” and CIGS prefers a substrate. One advantage of the “substrate” is the ease with which the thin film PV can be deposited onto flexible substrates such as polyimides and stainless steel. Until recently the need for “superstrate” thin film PV to be deposited onto highly transparent materials has meant that the structure is rigid where thick (3 mm) architectural glass is commonly used. This view is rapidly changing with reports of high efficiency thin film CdTe PV onto 100 µm thick glass, known as ultra-thin glass (UTG) with NREL reporting on over 16% efficiency cells on Corning Willow glass and the authors of this paper reporting on over 15% cells on space qualified microglass. This invited talk will make the case for thin film PV on UTG as a means of achieving high power to weight ratio and flexible solar cells for new terrestrial and space applications. The issue of strength and durability will be addressed along with the potential for high volume manufacturing based on roll-to-roll processes.

Authors : Sankara Rao Gollu a, Ramakant Sharma a, G. Srinivas a, Souvik Kundu b,1, Dipti Gupta a
Affiliations : a Plastic Electronics and Energy Lab (PEEL), Department of Metallurgical Engineering and Material Science, Indian Institute of Technology Bombay, Mumbai, 400076, India b School of Electrical Engineering and Computer Science, Oregon State University, 1148 Kelley Engineering Center, Corvallis, OR 97331, USA

Resume : It is well known that organic solar cells (OSCs) with inverted geometry have not only demonstrated a better stability and longer device life time but also have shown improved power conversion efficiency (PCE). Recent studies exhibit that incorporation of metal and/or semiconducting nanoparticles (NPs) can further increase the PCE for OSCs. In this present work, we have synthesized SiO2 NPs and Cu2S nanocrystals and incorporated them into P3HT: PCBM photoactive layer in order to investigate the light trapping effects in an OSC. Absorption studies have shown a considerable increase in photo absorption in both the cases. The fabricated devices having the structure ITO/ZnO (NPs)/P3HT: PCBM:Nanoparticles/MoO3/Al on insertion of SiO2 NPs and Cu2S nanocrystals also demonstrated significant enhancement in PCE. Mott–Schottky analysis and impedance spectroscopy measurements have been carried out to determine the depletion width and global mobilities for both the devices. With the help of these results, the possible reason for PCE enhancement and the efficacy after incorporation of SiO2 NPs and Cu2S nanocrystals in active layer were explained.

Authors : Xavier Jeanbourquin; Andrea Gasperini; Aiman Rahmanudin; Kevin Sivula
Affiliations : Ecole Polytechnique fédérale de Lausanne (Switzerland)

Resume : PBTTT remains a unique polymer semiconductor due to its ability to self-assemble into 2D lamellar structures, which give rise to a high hole mobility.1 Recently, we have shown that the hole mobility of thin films PBTTT strongly depends on its number average molecular weight (Mn), which affects the morphology.2 Despite the impressive performance, PBTTT performs poorly in bulk heterojunction (BHJ) solar cells due to the formation of a co-crystal (CC) phase in presence of PCBM. Obtaining the ideal BHJ morphology where both pure donor and acceptor phases can coexist with a blended phase remains a key challenge. Here, we demonstrate by using different PBTTT Mn, and combining two acceptors (PCBM and bisPCBM) a strategy to control the morphology and the distribution of pure and CC phases in BHJ solar cells. AFM as well as nanomechanical mapping are used to identify the different domains. Formation of the CC is characterized by photoluminescence spectroscopy and DSC. The changes in device performance metrics corresponding to distinct morphologies are further investigated by impedance spectroscopy to gain further insight into the role of charge transport and recombination. Overall, the results suggest that a complete control of the BHJ can be achieved by taking advantage of the CC formation combined with different Mn, leading to higher power conversion efficiencies. 1) Gasperini et al, Chem. Sci. 2014, 5, 4922. 2) Gasperini et al, Macromolecules 2013, 46, 9349

Authors : Masato Ishikawa1, Takahashi Nakayama1 , Kazuki Wakita 2, Nazim Mamedov 3
Affiliations : 1Department of Physics, Chiba University; 2Department of Electrical, Electronics and Computer Engineering, Chiba Institute of Technology; 3Institute of Physics, Azerbaijan National Academy of Sciences

Resume : TlInSe2 is a ternary compound made of one-dimensional InSe2 and Tl chains and shows low-dimensional electronic and optical properties. Recently, it was reported that TlInSe2 changes to an incommensurate (IC) phase when grown below 410K and shows a giant thermoelectric power around 106μV/K, thus expected as a promising material. The appearance of large thermoelectric power is expected related to the structural phase transition from high-temperature commensurate to low-tem- perature IC phases. However, it is still unknown what crystal structure is realized and why such giant ther-moelectric power appears. We studied electronic struc-ture of TlInSe2 using the first-principles calculation and found that Tl atoms largely move from the high-temperature positions and produce a staggered chain. In case of high-temperature phase, The lower conduction bands of Tl-s orbitals. In particular, because Tl atoms are located nearby along the c axis, the band width of the low-est conduction band is large. In case of low- temperature phase, The lowest conduction-band at T (0.5,-0.5,0.5), thus the band gap becoming indirect. The lower conduction bands around T are made of In-s orbitals. It is noted that the dispersion of conduction bands is remarkably small in a low-temperature phase, which reflects the staggered atom positions of Tl and In. As a result, we can expect that the conduction-band bottom has a large density of states. This feature might explain why the thermoelectric power is large

15:30 Coffee break    
Authors : Brigitte Pecquenard1, Frédéric Le Cras2, Vincent Pelé1,2, Florian Flamary1,2
Affiliations : 1CNRS, Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac, France 2Univ. Grenoble Alpes, F-38000 Grenoble, France CEA, LETI, Minatec Campus, F-38054 Grenoble cedex, France

Resume : The significant growth of portable electronics, generally battery-powered, has triggered the race for the development of high-performance microprocessors, Systems-on-a-Chip (SoCs) or DRAM, using low power consumption integrated circuits. As a consequence, the energy supply of such optimized components can be operated today also by miniaturized power sources such thin film Li or Li-ion batteries (1 to 500 µAh). They are built up through the deposition by PVD techniques of current collectors, the positive electrode, the electrolyte and the negative electrode on a rigid or flexible substrate. Actually, about ten layers are stacked to form a complex system with a total thickness of about 10 µm. The choice of the active materials (electrodes, electrolyte) appears quite different from the one for conventional Li-ion batteries due to the specific applications of these micro-power sources and their manufacturing process. Therefore, our aim is to tailor thin film properties by tuning the sputtering parameters in order to improve the performance of each active constituent of the cell as well as the overall behavior of the microbattery [1-4]. As for positive electrode materials, most studies focused up to now on intercalation compounds (LiCoO2, LiMn2O4, V2O5…) despite their limited capacity (65-115 µµm-1). A mean to improve the capacity of the microbattery consists in considering compounds reacting with lithium according to a conversion reaction, hence having a far larger theoretical capacity. Thin films of FeS2 [4] in particular were found to deliver reversible capacities above 300 µµm-1 with an excellent cycling stability. [1] V. P. Phan, B. Pecquenard, F. Le Cras, Adv. Funct. Mater., 22 (2012) 2580-2584 [2] M. Ulldemolins, F. Le Cras, B. Pecquenard, Electrochem. Comm., 27 (2013) 22-25 [3] B. Pecquenard, F. Le Cras, D. Poinot, O. Sicardy, J.P. Manaud , ACS Appl. Mater. Interfaces, 6 (2014) 3413-3420 [4] F. Flamary, V. Pelé, L. Bourgeois, B. Pecquenard, F. Le Cras, Electrochem. Comm., 51 (2015) 81-84

Authors : E. Senokos 1 2, R. Marcilla 2, J.J. Vilatela 1, V. Reguero 1, J. Palma 2
Affiliations : [1] IMDEA Materials Institute, Eric Kandel 2, Madrid, Spain; [2] IMDEA Energy Institute, Av. Ramón de la Sagra 3, Mostoles, Madrid, Spain

Resume : Carbon nanotubes fibers have been synthesized by the direct spinning process from the gas-phase during growth of CNTs by floating catalyst chemical vapor deposition. This method enables the production of kilometres of macroscopic fibres that can be assembled as films. In this work, we show that such materials are good candidates as electrodes for robust supercapacitors. They combine: high-performance mechanical properties, such as specific tensile strengths around 1 GPa/SG, modulus close to 40 GPa/SG, toughness of 36 J/g and high-flexibility; high electrical conductivity (3.5x10^5 S/m), and high specific surface area (˃ 100 m^2/g). The intrinsic electrochemical performance of CNT fibers is studied by cyclic voltammetry in three-electrode system using PYR14 TFSI as ionic liquid electrolyte. The results show a capacitance of 54 F/g at 10 mV/s and 3.5 V. Symmetric supercapacitor devices produced by assembling two CNT fibers electrodes and PYR14 TFSI electrolyte were also tested. The devices have an energy density of 11 Wh/kg and power density of 11 kW/kg at 5 mA/cm^2 and 3.5 V. A comparison of specific capacitance and toughness of CNT fibers (54 F/g and 36 J/g) with activated carbon (80 F/g and 0.2 J/g) and carbon fibers (1.3 F/g and 19 J/g) shows potential applications of this material in multifunctional structural supercapacitors.

Authors : L. Simonelli1, W. Olszewski1, 2, M. Avila Perez1, C. Marini1, T. Mizokawa3, 4, N.L. Saini5, and T. Broux6 ,7, L. Croguennec6, F. Fauth1, M. Bianchini6, 7, 8, C. Masquelier7
Affiliations : 1Alba Synchrotron Light Facility, Crta. BP 1413, Km. 3.3, 08290 Cerdanyola del Vall?es, Barcelona, Spain, EU 2Faculty of Physics, University of Bialystok, 1L K. Cio lkowskiego Str., 15-245 Bia lystok, Poland, EU 3Department of Physics, University of Tokio, 5-1-5 Kashiwanoha, Kashiwa, Chiva 277-8561, Japan 4Dep. of Complexity Science and Engineering, Univ. of Tokio,5-1-5 Kashiwanoha, Kashiwa, Chiva 277-8561, Japan 5Dipartimento di Fisica, Universit?a di Roma ?La Sapienza? - P. le Aldo Moro 2, 00185 Roma, Italy, EU 6Institut de Chimie de la Mati?re Condens?e de Bordeaux (ICMCB), Univ. Bordeaux, Bordeaux INP, Pessac, France 7Laboratoire de R?activit? et de Chimie des Solides (LRCS), Universit? de Picardie Jules Verne, Amiens, France 8Institut Laue-Langevin, Grenoble, France

Resume : The raising necessity in energy conversion and storage requires a constant development of cathodes with higher energy and power densities as well as cost-effectiveness, safety, sustainability, eco-friendliness, rate capability, and large-scale manufacturing. Beside lithium ions derived cathode materials, whose outstanding electrochemical performance have been demonstrated in Lithium-ion batteries [1, 2], several sodium-rich cathode materials have been recently proposed. Indeed, sodium-ion batteries have attracted growing attention because of the natural abundance and low toxicity of sodium [3-5]. The lifetime and efficiency of a battery are obviously key points, and are strongly related to the reversibility of deintercalation and intercalation reactions. During the charging/discharging processes the cathode crystal structure could undergo bond variations that have direct consequences on the reversibility of ion migration in the cathode [1,6,7]. For example it has been shown that the structural and electronic properties of the layered cobaltate NaxCoO2 vary after electrochemical intercalation or deintercalation of sodium [8, 9] strongly influencing the incredibly high Na diffusion speed [10]. More in general distortion could not occur at long range and could not be detected by conventional diffraction techniques. X-ray absorption spectroscopy (XAS) is the most suitable technique to access to the local structure as a function of the charge state, giving at the same time access to complementary information about the electronic properties. Here we report on the sodiation/desodiation effects on the local electronic and structural properties of NaxCoO2 cathode material by an ex-situ temperature dependent Co K-edge X-ray absorption spectroscopic study, comparing the obtained results with those gathered at the most used LixCoO2 material, and demonstrating clearly different intercalation chemistry for the two systems. This result reinforces the suitability of NaxCoO2 for applications and clearly underlines the key role of local atomic displacements in the CoO6 octahedra and disorder, being limiting factors for the diffusion and the reversibility of ions in cathodes for batteries. Finally we report on the operando investigation of the redox processes involved during sodium deintercalation from the Na3V2(PO4)2F3 cathode material [11]. X-ray absorption near edge structure measurements collected at the V k-edge finally reveal the charge compensation mechanism on the V site, in a system where a complex phase diagram is formed as a function of the charge state [12]. References: [1] J. M. Tarascon and M. Armand, Nature, 2001, 414, 359?367; [2] J. M. Tarascon, Philos. Trans. R. Soc., A, 2010, 368, 3227?3241; [3] H. K. Song, K. T. Lee, M. G. Kim, L. F. Nazar and J.Cho, Adv. Funct. Mater. , 2010, 20, 3818?3834; [4] V. Palomares, P. Serras, I. Villaluenga, K. B. Hueso, J. Carretero-Gonzalez and T. Rojo,Energy Environ. Sci., 2012, 5, 5884?5901; [5] B. L. Ellis and L. F. Nazar, Curr. Opin. Solid State Mater. Sci., 2012, 16, 168?177; [6] J.B. Goodenough, Y. Kim, Chem. Mater. 22 (2010) 587; [7] P. He, H. Yu, D. Li, H. Zhou, J. Mater. Chem. 22 (2012) 3680; [8] Q. Huang et al., PHYSICAL REVIEW B 70, 184110 (2004); [9] R. Berthelot et al., Nature Materials 10, 741780 (2011); [10] Takayuki Shibata et al., SCIENTIFIC REPORTS 5, Article number: 9006 (2015); [11] M. Bianchini, N. Brisset, F. Fauth, F. Weill, E. Elkaim, E. Suard, C. Masquelier and L. Croguennec, Chem. Mater., 26(14), (2014), 4238; [12] M Bianchini, F Fauth, N Brisset, F Weill, E Suard, C Masquelier, and L. Croguennec, Chem. Mater. 27 (8), (2015) 3009

Authors : Alfonso Sepulveda1,2, Brecht Put1,3, Nouha Labyedh1,2, Philippe. M. Vereecken1,2
Affiliations : 1-Imec, Kapeldreef 75, 3001 Leuven, Belgium 2-Centre for Surface chemistry and Catalysis, KU Leuven, Kasteelpark 23, 3001 Leuven 3-Department of Physics, KULeuven, Celestijnenlaan 200D, 3001 Leuven

Resume : Lithium-ion batteries (LIB) have gained much attention in portable consumer electronics due to their high-energy density, high voltage, excellent shelf life and safety. LIB’s have the highest energy density of all known systems and are thus the best choice for rechargeable micro-battery applications. Liquid electrolyte based batteries present limitations in safety, size and design, thus all-solid state devices are predominantly considered to overcome these restrictions. Although planar all-solid state thin-film lithium and lithium-ion batteries are at present commercially available they have low capacity (<1mAh/cm2) which limits their application scenario. The main challenges in the introduction of all-solid state Li-ion batteries are low ionic conductance and limited cycle life time due to mechanical stress and shearing interfaces. Novel materials and innovative nanostructures have to be explored in order to overcome these limitations. The capacity can be increased by coating the thin film battery stack on micro-or nanostructured surfaces (3D thin-film batteries) without increasing film thickness. The increase in surface area through 3D structuring increases the available capacity and also increases the maximum current and thus the battery power. Thin film 3D compatible materials need to provide with the necessary requirements for functional and viable thin-film stacks. Thin film electrodes offer shorter Li-diffusion paths and high gravimetric and volumetric energy densities which allow them to be used at ultra-fast charging rates while keeping their high capacities. Thin film electrolytes with intrinsically high ion conductivity (~10-3 do exist, but are not electrochemically stable. On the other hand, electronically insulating electrolytes with a large electrochemical window and good chemical stability to metallic Li are known, but typically have intrinsically low ionic conductivities (<10-6 S cm). LiMn2O4 (LMO) and Li4Ti5O12 (LTO) are among the most interesting electrode candidates for thin film batteries offering low cost, low toxicity, high voltage and high capacity. The Energy Storage Group of IMEC has shown the feasibility and promise of LMO and LTO as conformal films for 3D thin film battery applications. In this paper, we focus on the effect of downscaling of the film thickness on rate performance and cycle stability of LMO thin film cathode layers created by RF-sputtering. Planar LMO thin films between 25 nm and 500nm have been electrochemically characterized. The thinnest films below 100nm show the highest volumetric capacity and the best cycling stability, retaining the initial capacity over 70 (dis)charging cycles when manganese dissolution is prevented at 1C. The increased stability of the films below 50 nm allows cycling in both the 4 and 3V potential region, resulting in a high volumetric capacity of 1.2Ah/cm3. Also, the creation of LTO anode layers through a post-lithiation process of TiO2 is demonstrated here. Planar LTO thin films below 100 nm have been electrochemically characterized. A 70 nm film retains 85% of its original capacity after 100 (dis)charging cycles at 10C. These layers can be implemented into a high aspect ratio 3D pillar structure arrays.

Authors : B. Breitung, A. Schneider, P. Baumann, H. Sommer, J. Janek, T. Brezesinski
Affiliations : B. Breitung 1; A. Schneider 1; P. Baumann 2; H. Sommer 1,2; J. Janek 1,3; T. Brezesinski 1 1:Battery and Electrochemistry Laboratory (BELLA), Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany 2: BASF SE, 67056 Ludwigshafen, Germany 3: Institute of Physical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany

Resume : Nanoscale silicon (Si) is gaining significant attention as anode material for rechargeable lithium-ion batteries (LIBs) in recent years. Part of the reason for this is the high abundance of silicon and its exceptionally high theoretical gravimetric and volumetric capacity when fully lithiated (corresponding to Li22Si5). This capacity is much higher (approx. 4200 mAh/g or 9800 mAh/cm?) than that of graphite (372 mAh/g or 840-1200 mAh/cm?), which is currently the benchmark anode material in LIBs. Nevertheless, severe issues arise from large volume expansion upon alloying with Li. This volume change adversely affects the cyclability, thereby impeding the use of silicon anodes on a commercial level. The areal capacity of Si-containing anodes must be sufficiently high (>2 mAh/cm?) for ?real world? applications. Here, we report on a systematic study of Si-based electrodes with various loadings ? the goal was to find a good balance between stability and areal capacity. Furthermore, we describe a novel pyrolysis process to produce advanced carbon/silicon nanocomposites, able to dramatically improve cycling performance, including rate capability and capacity retention. Batteries using our carbon/silicon nanocomposites demonstrate specific capacities >2000 mAh/g at C/2 and areal capacities >2 mAh/cm? over hundreds of cycles. All materials employed were thoroughly analyzed via TEM, Raman spectroscopy, and galvanostatic charge/discharge measurements. In addition, we present insights into the cell ?breathing? and SEI formation from in operando AFM.

18:00 Best Presentation Awards Ceremony and Reception (Main Hall)    
Start atSubject View AllNum.
09:00 Plenary Session - Main Hall    
12:30 Lunch break    
Authors : Anna-Lisa Chaudhary,1 Natalia Aubrift,1 Klaus Taube,1 Giovanni Capurso,1 Guanqiao Li,2 Motoaki Matsuo,2 Shin-ichi Orimo,2 Claudio Pistidda,1 Thomas Klassen1 and Martin Dornheim1
Affiliations : 1Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Geesthacht , Germany; 2WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan

Resume : Hydrogen technology can be incorporated into intermittent renewable energy systems to realize a complete clean, green energy harvesting and storage cycle. An efficient hydrogen storage system based on solid state hydrogen requires optimized material – tank systems to enable the storage of excess energy produced from sustainable energy sources to be used at times when direct production from renewables is not possible. High pressure tanks up to 700 bar are becoming more and more cost effective, thus opening up new potential for high pressure hydrogen storage materials. Complex hydrides are very promising hydrogen-storage materials, due to their high gravimetric and volumetric capacities. At moderate temperatures and pressures both borohydride and alanate systems have not yet met the criteria required for either mobile or stationary applications. However, these materials may have increased functionality once introduced into high pressure tank systems. Presented here are several complex hydride systems including light metal borohydrides composites with magnesium iron hydride, as well as lithium alanates combined with transition metal halide additives. Sorption properties of these systems will be discussed in relationship to the potential storage in high pressure hybrid tank systems.

Authors : J. Proost,* A. Delvaux, Q. de Radiguès, F. Van Wonterghem and Q. Van Overmeere (*
Affiliations : Division of Materials and Process Engineering, Université catholique de Louvain (UCL), Louvain-la-Neuve, Belgium.

Resume : The electrochemical production of H2 from water electrolysis is considered a promising route to store the electricity produced by intermittent renewable sources. This presentation will focus on a simple way to increase its efficiency by the use of 3-D porous electrodes. In a first part, we will discuss the use of commercial, macro-porous Ni electrodes with different geometries, including 1-D wires, 2-D plates and 3-D foams. From a quantitative analysis of chrono-potentiometric and linear sweep polarisation measurements, it was found that the cathodic overpotentials were lowest for the 3-D foam electrodes. Moreover, for the wire and plate electrodes, a sharp and sudden increase in potential was observed, which was taken as indicative for the appearance of a limiting current. This can be associated with mass transfer limitations for the hydrogen evolution reaction at these 1-D and 2-D electrodes [1]. In a second part, we will then demonstrate how an even better performance increase can be obtained by the use of nano-structured 3-D porous electrodes, obtained by magnetron co-sputtering of Al-Ni thin films followed by Al leaching in concentrated KOH solutions. We will also discuss how the morphology of these 3-D nano-porous Ni electrodes can be tailored as a function of their processing conditions, which in turn allows favouring bubble detachment. [1] Q. de Radiguès, J. Proost et al., Industrial & Engineering Chemistry Research 51 (2012) 14229.

Authors : X.B. Chen1,2 P. M. Vereecken1,2
Affiliations : 1 imec, Kapeldreef 75, B-3001 Leuven, Belgium 2 Centre for Surface Chemistry and Catalysis, University of Leuven, Kasteel-park Arenberg 23, B-3001 Leuven, Belgium.

Resume : Polymer electrolytes are considered as potential candidates for all-solid-state batteries. They have a good electrochemical window, low electronic conductivity and low cost, but their ionic conductivities still remains low (typically in order of 10-7 S/cm). The ionic conductivity can be augmented with about one order of magnitude by embedding inorganic nanoparticles such as SiO2 and Al2O3 into the polymer electrolyte as such forming a composite electrolyte (CE). Another way to circumvent the low conductivity issue, is to reduce the thickness of the electrolyte to decrease the total ionic conduction path. This concept is used in thin-film batteries. Unfortunately, thin polymer films are mechanically frail and prone to in diffusion and formation of metallic filaments. Therefore, we have combined the composite electrolyte and thin-film concept in one by introduction of the polymer/lithium salt mixture into a porous oxide thin-film. In this way, the mechanical stability is provided by the oxide while ion-conductivity is delivered by the enhanced interface conduction associated with composite electrolytes. In this work, we report for the first time the fabrication of a polyethylene glycol ( PEG)/LiX-porous SiOxCyHz thin film (~100nm) composite electrolyte. The composite electrolyte was fabricated by a two-step approach. . First the porous SiOxCyHz film was deposited on the electrode substrate by PECVD. The porous film was then filled with the PEG/LiX mixture. The filling of the polymer/LiX into the porous structure was 90% reducing the porosity of the structure to less than 1% after filling, as determined from ellipsometric porosimetry (EP). The insulating SiOxCyHz thin film was converted into a Li conductor and the conductivity of the electrolyte reached up to 2x10-7 S/cm. The effect of the anion of the LiX salt as well as the molecular weight of the PEG on the conductivity of the CE was investigated. The electrolyte with smaller anion showed higher conductivity and the electrolyte with the lower molecular weight polymer yielded higher conductivity.

Authors : Jürgen Wackerl, Klaus Wippermann, Carsten Korte
Affiliations : Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research (IEK-3), Germany

Resume : Ionic liquids (ILs) are a promising materials class as alternative electrolytes for high temperature polymer fuel cells (HT-PEFCs) to overcome long standing problems especially concerning the electrodes. Among the ILs the subclass of protic ILs (PILs) have the biggest potential as an alternative to the commonly used ortho-phosphoric acid electrolyte, since they can provide proton conductivity even in the absence of water while still maintaining chemical and electrochemical stability. Several PIL compounds with high chemical acidity have already been examined which show reasonable proton conductivity compared to phosphoric acid, especially at temperatures around 100°C. However, higher temperatures must be achieved for the application in HT-PEFCs and the thermal stability even over long operating times becomes crucial. The correlation of experimental derived thermal stability parameters and the acidity of the PILs compounds will be discussed on the example of [2-Sea]+[TFO]- as model compound. A main focus will be laid on the determination of the thermal stability since several methods are available.

15:30 Coffee break    
Authors : Antonio Ferreira da Silva
Affiliations : Instituto de Física, Universidade Federal da Bahia, Campus Ondina, 40210 340 Salvador, Bahia, Brazil

Resume : Photocatalytic materials have gained remarkable attention in the field of solar fuel production, which is a promising approach for efficient solar energy conversion and storage [1]. Among other oxides, doped BiNb(Ta)O4 and TiO2 have been identified as potential photocatalytic materials due to their appropriate band gap energies. We have prepared high quality materials. The first by the citrate method according to reference [2] and the latest by both, a modified ion beam assisted deposition technique [3] and as titanium dioxide nanotubes (TiO2-NTs) arrays synthesized by electrochemical anodization [4], confirmed by low temperature photoluminescence and absorption. We present the optical properties spectra of TiO2 and doped BiNb(Ta)O4 using the X-ray Photoelectron Spectroscopy (XPS) and first principles approach by DFT respectively [2]. In this work, position of reduction and oxidation level with respect to the vacuum level are identified for these materials. We have calculated the work function of these materials and aligned the redox potential levels to the VBM and CBM. We can conclude that they are good candidates for the production of hydrogen by splitting of water in the presence of sunlight. This work is supported by the Brazilian agencies CNPq and FAPESB. [1] N. S. Lewis and D. G. Nocera, PNAS, 103, 15729 (2006) [2] C. G. Almeida, R. B. Araujo, R. G. Yoshimura, A. J. S. Mascarenhas, A. Ferreira da Silva, C. M. Araujo, L. A. Silva, Int. J. Hyd. Energy 39, 1220 (2014). [3] M. Kumar, G.Baldissera, C.Persson, D.G.F.David , M.V.S.da Silva , J.A.Freitas Jr., J.G. Tischler , J.F.D.Chubaci, M.Matsuoka , A.Ferreira da Silva, , J. of Crystal Growth 403, 124 (2014). [4] X. Chen and S. S. Mao, Chemical Reviews 107, 2891 ( 2007)

Authors : Herrera, D. B. 1, Galvan, E.1 and Rodr?guez, S. 1
Affiliations : 1 GPTech, Camino de los Descubrimientos, 17, Seville, SPAIN

Resume : Gallium Nitride (GaN) is an advanced semiconductor material, which represents a huge potential to enable innovations to power converters, including Solar Inverters. The deployment of this technology is the key for the challenges on energy efficiency and renewable energy. A GaN-based three-phase power inverter topology is designed for photovoltaic (PV) applications. Improvements in total efficiency in innovative PV solar power DC/AC inverter have been demonstrated. Performance comparison of high voltage normally-off GaN FETs versus Silicon and Silicon Carbide based devices has been presented. The proposed 100 kW inverter with 20 kHz switching frequency consists of use the new GaN technology to improve the efficiency, to reduce the costs, the system volume and weight and with increased output power. The main objective of this GaN-based PV power inverter is to be able to achieve higher voltage, lower leakage, reduce the power dissipation, passive components and demonstration of high reliability and lifetime technology. Some challenges with the manufacturing capabilities have to be proved to obtain material quality, low cost and high handling. The PV inverter is verified by the GaN thermal design characteristics by PLECS Plexim simulation software and the electrical characteristics, the passive components definitions and the high frequency switching are simulated by PSCAD software. A test-bench prototype is going to be built to verify the high efficiency of the GaN-based.

Authors : Aadesh P. Singh and Bodh R. Mehta
Affiliations : Department of Physics, Indian Institute of Technology Delhi, Hauz, Khas, New Delhi110016, INDIA

Resume : Photoelectrochemical (PEC) splitting of water appears to be the most promising, economically viable and sustainable way for the production of hydrogen. Although, there are a series of new engineering strategies which have emerged towards development of highly efficient PEC water splitting for hydrogen generation. Yet, finding an optimal material for PEC cell is a very difficult task due to three main requirements in a single material system: 1) chemical stability 2) visible light absorption and 3) band edges matching to redox levels of water. This talk will summarize the major results obtained in the last years for photoelectrochemical water splitting. Our attention has been devoted to further modify the old workhorses viz. α-Fe2O3, TiO2 and BiVO4 etc by using various engineering strategies such as band structure engineering, material disordering, nano/micro engineering, surface/interface engineering to improve the performances of metal oxide-based materials, especially favoring the photoelectrochemical activity under simulated sunlight. Recently, a new engineering strategy, i.e., band re-alignment of BiVO4/TiO2 at the heterostructure was achieved by gas–phase modification technique of the top TiO2 layer which strongly promotes interfacial interaction at the junction and leads to an effective interfacial charge separation and charge transport. The modified BiVO4/TiO2 heterostructures exhibit significant enhancement of visible light absorption and improve the photoelectrochemical response.


Symposium organizers
Joanna K. BENDYNAMintres B.V.

De Nieuwe Erven 8 5431 NT Cuijk, The Netherlands
John F. ZEVENBERGENTNO - Netherlands / Organisation for Applied Scientific Research

Lange Kleiweg 137 2288 GJ Rijswijk The Netherlands
Rajeev AHUJADepartment of Physics and Astronomy, Uppsala University

Box-516 SE-75120 Uppsala, Sweden
Sudip CHAKRABORTYApplied Materials Physics, Royal Institute of Technology (KTH) Stockholm

SE-10044 Stockholm, Sweden