Advanced materials for printing
Printed Electronics is an emerging field in which conventional printing technologies, both analog and digital, are utilized to manufacture a variety of electronic devices thanks to the development of a wide range of solution processable functional materials, including metals, insulators, and semiconductors.
The scope of the symposium is to collect innovative ideas in the field of Printed Electronics. This subject has promised to revolutionize the manufacturing of electronic devices, achieving very low fabrication costs of large area devices thanks to additive, low temperature processes, and on the other our daily life, promoting the ubiquitous applications of microelectronics and sensors in wearable components and conformable devices. Additive fabrication process is in contrast to traditional micro-fabrication processes that rely critically on subtractive patterning. Nanostructured / nanoengineered materials are ideal additive building blocks for additive processes such as those used in Printed Electronics, since they allow control over size distribution, dimensionality and carrier wavefunctions confinement, any physical / chemical property. Traditional high throughput printing of plastic sheets, paper, fabric, is done using fast rotary machines. Printed Electronics technologies involve the same analog process, in particular screen printing, gravure printing / imprinting, flexographic printing. The contact between the transferred ink and the desired substrate, its subsequent motion under the joint influence of surface tension interaction with the substrate, the evaporation of the solvent, the time-dependent viscosity of the variable mass ink system, the interaction with the ambient in terms of temperature and humidity, the post-printing treatments to induce functional properties (e-beam, light, UV, laser, thermal, microwave, magnetic, etc.), are all examples of the aspects evaluated by actual research. Besides this, digital processing involves a layer by layer construction of two-dimensional or three-dimensional objects using a liquid ink fed into a printhead, operated by an electronic driver thanks to a transducer (piezoelectric, piroelectric, magnetostrictive, electroacustic, magnetohydrodynamic, etc.
Hot topics to be covered by the symposium:
- Digital Printing (thermal inkjet, piezoelectric, magnetohydrodynamic, new approaches, fully printed circuits, new functional inks like CNTs, graphene, graphene oxide, sintering, electronic, magnetic, surface and photonic properties of printed materials);
- Analog Printing (roll-to-roll, gravure, flexography, rotary serigraphy, fully printed circuits, new functional inks, electronic, magnetic, surface and photonic properties of printed materials);
- Emerging Roll-to-Roll equipments (R2R Sputtering, R2R Atomic Layer Deposition);
- Substrate Materials – Nanocellulose, Paper, Silk, Technopolymers;
- Technologies (plasma treatments, laser drilling and processing).
Tentative list of invited speakers:
- Ronald Österbacka, Åbo Akademi University – «Printed Electronics on Paper»
- Graham Martin, Uni Cambridge - «Latest in inkjet technology»
Tentative list of scientific committee members:
- M. Caironi, Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Italy
- Jukka Hast, VTT Technical Research Centre of Finland
- Stefan Güttler, Media University, Stuttgart, Germany
- Martin Möller, DWI – Leibniz-Institut für Interaktive Materialien e.V., Aachen, Germany
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SESSION 1 : -
Authors : Yi Zhang & Patrick J. Smith
Affiliations : Mechanical Engineering, University of Sheffield, Sheffield, United Kingdom
Resume : This talk discusses tougher and stronger carbon fibre composites that have been produced using inkjet printing to deposit polymer droplets onto the composite precursor. The polymer systems used are either a single material system, PMMA or a dual material system, PMMA and PEG. The resultant uni-directional carbon fibre composites exhibit improved mechanical properties with a barely noticeable increase in weight (~0.025 wt%). For the single material PMMA system, interlaminar fracture toughness is increased by 40%, with evidence that higher values are possible. For the dual material system, a similar improvement in interlaminar fracture toughness is seen alongside a significant increase in apparent interlaminar shear strength.
Authors : Jang-Ung Park
Affiliations : School of Materials Science & Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, 689-798, Republic of Korea e-mail: email@example.com Group website: http://wearable.unist.ac.kr
Resume : As predicted in Moore’s law, overall processes of micro- and macro-electronics have become very complicated and their fabrication costs also have risen exponentially. Therefore development of simplified, low-cost processes with suitability for next-generation electronic materials is an important research topic. Especially, emerging flexible electronics, that uses plastic substrates rather than glasses and wafers, shows strong demands on the innovative processing technologies due to the limitation on process temperature. This talk presents the fabrications of various flexible, stretchable, and transparent electronic devices, including integrated oxide semiconductor transistor arrays, OLED displays, touch screen panels, and wireless bio- or pressure sensors, as wearable forms. High-resolution 2D or 3D printing techniques based on an electrohydrodynamic inkjet method can assist these unconventional fabrications. In addition, we also present synthesis of functional nanomaterials, including graphene and metal nanowires, and their uses for transparent, flexible electronics. The printing process with combinations of nanomaterials suggests the substantial promise of future electronics.
Authors : Sebastian Gerke; Jonas Zürcher; Luca Del Caro; Thomas Brunschwiler
Affiliations : IBM Research – Zurich, Säumerstrasse 4, 8803 Rüschlikon
Resume : Copper is the metal of choice for conductive paths in electronics. It is lower in cost than silver and offers excellent electrical properties like low electrical resistivity. Physical vapor deposition and etching or electroforming are the standard processes used to structure copper on silicon and printed circuit board technology. Recently, copper inks and pastes are available to print copper with possibly lower production costs than the established processes. Hence, printing is attractive for flexible electronics now. Technological specifics of the inkjet and screen printing limits the printable size of structures, especially on hard and less absorbent materials like silicon. The authors will present their latest results in relief printing of conductive structures on unconditioned standard chemical polished silicon wafers as well as on insulating oxides. A novel high viscous copper paste containing nano and micro particles is transferred by a deep reactive ion etched silicon stamp from a coated carrier to the sample. Test series have shown that the linewidth as well as the pitch between neighboring relief printed structures can be as low as 10 µm. Sheet resistances of less than 10 mΩ/sq after formic acid assisted sintering at 200°C could be achieved. Further, the authors will give an overview on design rules for the stamp to obtain the desired geometry of printed structures and to minimize imperfections.
Authors : S. Calvi, F. Maita, M. Rapisarda, G. Fortunato, V. Preziosi, A. Cassinese, L. Mariucci
Affiliations : CNR-SPIN UoS di Napoli, Dipartimento Scienze Fisiche Università di Napoli, Facoltà di Ingegneria, Piazzale Tecchio 80, 80125 Napoli, Italy; IMM-CNR, Via del Fosso del Cavaliere 100, 00133, Roma, Italy; IMM-CNR, Via del Fosso del Cavaliere 100, 00133, Roma, Italy; IMM-CNR, Via del Fosso del Cavaliere 100, 00133, Roma, Italy; Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale - Dipartimento di Fisica, Università degli Studi di Napoli Federico II, Piazzale Tecchio 80, 80125 Napoli, Italy; CNR-SPIN UoS di Napoli, Dipartimento Scienze Fisiche Università di Napoli, Facoltà di Ingegneria, Piazzale Tecchio 80, 80125 Napoli, Italy; IMM-CNR, Via del Fosso del Cavaliere 100, 00133, Roma, Italy
Resume : In this work, we have carried out the characterization of conductive and dielectric inks for gravure printing, whose printability has been tested using a custom-made glass master fit in a commercial laboratory gravure printer. We have fabricated the new glass plate by photolithography to overcome the limits of the traditional metallic master, as we have proved during system validation. Indeed it allows to obtain smoother edges and nice cells profiles. The cleaning procedure is easier and effective, preventing clogging issues. Moreover, glass plate surface can be functionalized to increase contact angle, until being more hydrophobic than the substrate, to improve ink transfer. We combine this plate with the use of plastic blades to better ink transfer and to avoid metallic particles dispersion due to wear. By using our modified gravure printer, we have tested some conductive or dielectric inks to develop new formulations suitable for microelectronics applications, e.g. OTFTs. In detail, we have considered different formulations of PEDOT:PSS or dispersions of silver nanoparticles, and some commercial polymeric dielectrics. We have measured inks rheological properties and surface tension to evaluate their fluid dynamic properties. Their printability has been then verified through a run of printing tests. The films has been analysed by optical microscopy and AFM. Furthermore, we have realized MIMs with the dielectric inks to analyse the electrical properties of dielectric film.
Authors : Francesco Pastorelli, Thomas M. Schmidt, Markus Hösel, Roar R. Søndergaard, Mikkel Jørgensen and Frederik C. Krebs
Affiliations : Solar group, Energy department, Technical University of Denmark, Roskilde, Denmark
Resume : The footprint of organic electronic technologies is important when united in complex circuitry. We present flexible organic power transistors prepared by fast (20?m?min?1) roll-to-roll flexographic printing of the drain and source electrode structures, with an interspace below 50 um, directly on polyester foil. The devices have top gate architecture and were completed by slot-die coating of the organic semiconductor poly-3-hexylthiophene and the dielectric material polyvinylphenol before the gate was applied by screen printing. We explore the footprint and the practically accessible geometry of such devices with a special view toward being able to drive large currents while handling the thermal aspects in operation together with other organic printed electronics technologies such as large area organic photovoltaics (OPV) and large area electrochromic displays (EC). We find especially that an elevated operational temperature is beneficial with respect to both transconductance and on/off ratio. We achieve high currents of up to 45?mA at a temperature of 80?°C with an on/off ratio of 100 which is sufficient to drive large area organic electronics such as an EC device powered by OPV devices that we also demonstrate. Finally, we observe a significant temperature dependence of the performance which can be explored further in sensing applications.  Francesco Pastorelli, Thomas M. Schmidt, Markus Hösel, Roar R. Søndergaard, Mikkel Jørgensen and Frederik C. Krebs, " The Organic Power Transistor: Roll-to-Roll Manufacture, Thermal Behavior, and Power Handling When Driving Printed Electronics", Volume 18, Issue 1, pages 51?55, January 2016, doi: 10.1002/adem.201500348
Authors : S. Logothetidis1, C. Kapnopoulos1, E. Mekeridis2, A. Zachariadis1, V. Matskos2 and A. Laskarakis1
Affiliations : 1 Lab for Thin Films-Nanobiomaterials-Nanosystems & Nanometrology (LTFN), Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece 2 Organic Electronic Technologies P.C. (OET), Antoni Tritsi 21B, 57001 Thessaloniki, Greece
Resume : The emerging field of Organic and Printed Photovoltaics (OPVs) onto plastic substrates has the potential to revolutionize the generation of electricity from renewable sources and will enable the energy harvesting functionalities of consumer products. This is attributed to their numerous advantages that include their high degree of conformability to curved surfaces, tunable optical transparency and fabrication by low-cost production processes as roll-to-roll (r2r) printing. The main challenges to achieve the required OPV efficiency and stability for their commercialization is the optimization of the photoactive layer morphology and of the quality of printed nanomaterials. In this work, we present an overview of the unique methodology for the large area manufacturing of polymer-based OPVs on plastics by the unique r2r printing pilot line equipped with ultra-fast pulsed laser patterning of the different OPV layers (e.g., transparent electrodes, photoactive layers, metal electrodes) for the precise fabrication of polymer-based OPV device architectures nanometer scale. In addition, we report on a novel methodology for the ultra-fast in-line optical metrology and quality control of r2r printed OPV nanomaterials and devices by the adaptation of in-line Spectroscopic Ellipsometry (SE) and Raman Spectroscopy (RS) on this r2r printing pilot line. These optical techniques are combined with sophisticated modelling procedures and methodologies to obtain significant information on the optical properties, homogeneity, thickness, surface roughness and quality of bulk heterojunction photoactive layers for printed OPVs that consist of electron donors (e.g. polythiophenes) and acceptors (e.g. fullerene derivatives). The above demonstrate the importance and applicability of in-line precision tools for the efficient fabrication of OPV devices and robust determination of their thickness and quality for several Organic and Printed Electronics applications.
Authors : D. Kokkinos1, C. I. Chaidou1, M. Gioti1, I. Moutsios1, Ch. Kapnopoulos1, E. D. Mekeridis2, J.K. Kallitsis3,4, S. Logothetidis1
Affiliations : 1 Laboratory for Thin Films-Nanosystems and Nanometrology (LTFN), Physics Department, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece; 2 Organic Electronic Technologies P.C. (OET), Thessaloniki, Greece; 3 Department of Chemistry, University of Patras, University Campus, Rio-Patras GR26504, Greece; 4 Foundation for Research and Technology Hellas, Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Platani Str., Patras GR26504, Greece
Resume : Organic Light Emitting Diodes (OLEDs) are facing enormous growth in energy efficient lighting applications. Moreover, Polymer OLEDs (POLEDs) are giving the advantage of inserting wet techniques, which reduce rapidly the production costs, and increase potential commercial applications. In this work, we produce efficient POLEDs on flexible PET/ITO substrates with commercial and innovative active materials via gravure printing. The control of the emitting areas’ dimensions is realized through predefined pulsed laser patterning of ITO layer. Ink properties were primarily investigated and optimized with contact angle and viscosity measurements. The uniformity of poly (3,4-ethylene dioxythiophene): poly (styrene sulfonate) (PEDOT:PSS) and light emitting layers as well as topography were characterized with Optical Microscopy and Atomic Force Microscopy (AFM). The optimum thicknesses of all sequential layers consist the multi-layer structure of the POLED devices were determined by Spectroscopic Ellipsometry measurements. The Electro-Luminescence properties along with External Quantum Efficiency and Chromaticity Coordinates were investigated using an integrated sphere photonic system.
Authors : Nandini Bhandaru, Rabibrata Mukherjee
Affiliations : Indian Institute of Technology Kharagpur
Resume : In majority of the soft lithographic techniques, for every new design of patterns, a new original stamp or mold has to be fabricated by other lithography methods such as Photolithography or Electron Beam Lithography. The state of art now is to develop methods that are capable of producing structures which are not mere negative replicas of the original stamp. With this work, we report a facile nano patterning technique which makes it possible to create patterns of different periodicity and higher feature height, from a single stamp. The method is based on contact induced surface instability in a thin elastic film in proximity of a rigid contactor due to inter surface adhesive interaction. Exploiting the hysteresis between the bonding and the de-bonding stages, the method is capable of creating structures which are taller than the original patterns on the stamp. When a rigid grating pattern stamp is brought in contact proximity to a soft solid film, a positive replica of the stamp is formed on the film surface if there is a commensuration between the periodicity of the stamp features (λP) and the natural instability wavelength of the film, λ (≈ 3h, h is film thickness). Further proximity results in formation on of a perfect negative replica of the contactor patterns. De-bonding from this stage elongates the features, which are made permanent just ahead of detachment. On the other hand, if they are non-commensurate, the instability structures rather faithfully obey λ resulting in wide structures spanning several stamp stripes. Gradual detachment from the stage progressively narrows down the structure and enhances the gap between them, which allows fabrication of patterns with different duty ratio. The extent of stretching of the film ahead of detachment is seen to depend on the level of cross linking of the film, thereby allowing possible control of feature height.
Authors : Victor THENOT, Gaël DEPRES, Nadège REVERDY-BRUAS, Denis CURTIL, Mohamed SAADAOUI
Affiliations : Victor THENOT : Arjowiggins Creative Papers, 38500, VOIRON / Ecole nationale des Mines de Saint-Etienne, Centre de microélectronique de provence (EMSE/CMP), 13120 Gardanne / Université Grenoble Alpes, Laboratoire Génie des procédés papetier (LGP2), 38402 Saint-Martin d'Hères ; Gael DEPRES : Arjowiggins Creative Papers, 38500, VOIRON ; Nadège REVERDY-BRUAS : Laboratoire Génie des procédés papetier (LGP2), 38402 Saint-Martin d'Hères ; Denis CURTIL : Laboratoire Génie des procédés papetier (LGP2), 38402 Saint-Martin d'Hères ; Mohamed SAADAOUI : Ecole nationale des Mines de Saint-Etienne, Centre de microélectronique de provence (EMSE/CMP), 13120 Gardanne
Resume : Printed metal inks require a thermal step to evaporate the solvents and to trigger the particles coalescence. However, low-cost substrates like PET and paper have low thermal resistance, thus limiting the electrical performance obtained by using hot-air conventional processes. In this work, fast and selective methods, consistent with roll to roll manufacturing, were used to heat the ink without damaging the underneath substrate. First, lines were screen-printed on Powercoat paper (Arjowiggins) using silver microparticles and nanoparticles inks. Then sintering was done using photonics (Novacentrix) and near infrared (NIR, Adphos), and the performances were compared with that of conventional oven curing process at different temperatures (120 to 200°C). An in-situ electrical resistance measurement, in four-probe setup with acquisition speed up to 4 µsec, was used during sintering as a way to optimize and monitor the curing process. Finally ink thicknesses were measured by mechanical profiler to calculate the resistivity. We show that photonics process is more compatible with the use of silver nanoink because of better light absorption thus achieving higher temperature. The lowest resistivity at 7.9 µOhms.cm is achieved in 10 msec. On the other hand, silver microparticles absorb in the NIR and leads to 14.1 µOhms.cm in 1s, which is 30% to 50 % lowest than that of conventional oven. These results strongly confirm the potential of using selective sintering methods for R2R manufacturing of printed electronics devices on paper.
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SESSION 2 : -
Authors : F.S.Pettersson(1), T. Remonen(1),(2), D. Adekanye(1), C.-E. WilÃ©n(2), and R. Ãsterbacka(1)
Affiliations : (1)Physics, (2)Polymer Technology, Center for Functional Materials, Faculty for Natural Science and Engineering, Ã bo Akademi University, Finland firstname.lastname@example.org
Resume : Paper electronics is rapidly evolving and the possibility of extending the available information beyond the printed graphic is very interesting . Many of the suggested approaches are for example to improving logistics or disposable sensing, e.g.as food sensors on packages to minimize food spoilage. However, for paper electronics to be truly recyclable and/or disposable the components need be environmentally friendly and bio-compatible, and preferably operating at low voltages. Here we propose an environmentally safe approach to such active circuits and electronic functionalities, by making ion-modulated transistors on paper. By blending the semiconductor poly(3-hexyl thiophene) (P3HT) with a biodegradable poly-lactic acid (PLLA), and using solidified ionic liquids (ILs) tocreate solution-processable deep eutectic mixtures that areliquid or semiliquid at room temperature wehave created printable transistor structures and logic circuits operating at ~1V [2,3]. The use of the transistors in paper electronics based sensing applications for biologically relevant systems will be discussed and presented. References  D. TobjÃ¶rk and R. Ãsterbacka, Advanced Materials, 23, 1935-1961 (2011).  F. Pettersson, J. Koskela, T. Remonen, et al.,MRS Communications 4, 51-55 (2014).  F.Pettersson, T. Remonen, D. Adekanye, et al.,ChemPhysChem 16, 1286-1294 (2015)
Authors : Chin-Yu Hsu,Chien-Neng Liao
Affiliations : Department of Materials Science and Engineering;National Tsing-Hua University
Resume : Transparent conductors films (TCFs) are essential components in many optoelectronic devices. Indium tin oxide (ITO) has been widely used in TCFs due to its low sheet resistance and high visible light transmittance. However, the brittleness and rarity have restricted the application of ITO in flexible electrical devices. Metallic nanowires (NWs), like Ag NWs or Cu NWs, have become a promising alternative solution by forming a network structure on a transparent substrate. Although Cu is much cheaper than silver, oxidation of Cu NWs become a critical issue for electrical conduction and structure integrity considerations. In this study, Cu NWs were synthesized by pulsed electrodeposition with porous anodic aluminum oxide (AAO) templates. To improve their anti-oxidation property, a thin layer of silver was coated on the Cu NWs in a silver nitrate solution at room temperature through a galvanic replacement reaction. A filtration coating approach was used to fabricate the TCF with Cu-Ag NWs. We develop a thin film transfer process to embed the NW network in PMMA matrix, which not only provides a strong adhesion to the flexible substrate but also reduces the NWs contact resistance with an effective sheet resistance down below 10 Ω Sq-1. The study shall help the development of NW-based TCF technology for flexible electronic devices.
Authors : Bohores Villarejo(1), Cornelia Pop(1), Susagna Ricart(1), Jordi Farjas(2), Pere Roura(2), Teresa Puig(1), Xavier Obradors(1)
Affiliations : (1)Institut de Ciència de Materials de Barcelona (CSIC), Campus UAB, 08193 Bellaterra, Catalonia, Spain; (2)GRMT, Dept. of Physics, University of Girona, Campus Montilivi, Edif. PII, E17071 Girona, Catalonia, Spain
Resume : Chemical solution deposition (CSD) offers a versatile and low cost methodology for the production of coated conductors; however, reaching thick films (~1μm) by CSD becomes a great challenge due to the high stress produced during pyrolysis treatment, which may lead to buckling and crack formation and then decreasing the superconducting properties. Particularly, piezoelectric Inkjet printing (IJP) is presented as a robust and scalable technology to deposit by CSD YBa2Cu3O7 (YBCO) thick films starting from Y, Ba and Cu metalorganic low Fluor solutions with drop on demand single and multinozzle printheads. Ink formulation has been tuned using additives (i.e. diethanolamine, polyethylenglycol) to adapt the physicochemical and rheological properties to the printhead characteristics (viscosity, surface tension, solvent evaporation rates…) and also to control the interaction with the substrate (wettability, liquid distribution, drop fusion…) in order to obtain homogeneous and reproducible high performance YBCO films. In addition, these additives give toughness to the system avoiding defects during the pyrolysis treatment. We have performed an in-situ study (optical microscopy, interferometry) of the different stages during pyrolysis of the deposited films whose decomposition of the organic matter is identified by thermogravimetric, infrared spectroscopy and mass spectrometry analysis. All together our analysis has allowed defining the optimal heat treatment to prepare thick YBCO films.
Authors : Yejin Jo, Yeong-Hui Seo, Sunho Jeong, Youngmin Choi, Eui Duk Kim2, Seok Heon Oh2, and Beyong-Hwan Ryu†
Affiliations : 1. Advanced Materials Division, Korea Research Institute of Chemical Technology, 141 Gajeongro, Yuseong-gu, Daejeon 34114, Korea 2. Nano R&D Center, Hanwha Chemical Research & Development Center, 76 Gajeongro, Yuseong-gu, Daejeon 34128, Korea
Resume : For a decade, solution-processed functional materials and various printing technologies have attracted increasingly the significant interest in realizing low-cost flexible electronics. In this study, we report the preparation of highly conductive metal nanoparticle inks which can be successfully printed onto polymeric substrate and controlled the line width of printed inkjet-pattern. Cu nanoparticles were synthesized via the chemical reduction of Cu ions under inert atmosphere. To prevent interparticle agglomeration and surface oxidation, oleic acid was incorporated as a surface capping molecule and hydrazine was used as a reducing agent. To endow water-compatibility, the surface of synthesized Cu nanoparticles was modified. For reducing the surface tension and the evaporation rate of aqueous Cu nanoparticle inks, the solvent composition of Cu nanoparticle ink was investigated in the range of 30~70wt% of DI water with constant ratio of water mixable solvent. The effects of DI water content as a dispersion medium on rheology and solid concertation of aqueous based Cu nanoparticle ink for inkjet printing were investigated. The 40wt% aqueous Cu nanoparticle inks with 0.9wt% of dispersant showed the “Newtonian flow” and had a low viscosity under 10mPa∙S, which was applicable to inkjet printing. The line with of printed Cu patterns was controllable by the dispersion medium. The Cu patterns with a line width of 40~60㎛ were successfully fabricated, and which were depended on water content of dispersion medium. The 60wt% aqueous Cu nanoparticle ink was prepared with “Newtonian flow”. The resistivities of Cu patterns are measured to be ~10μΩ∙㎝ at annealing temperature of 300℃. (Ref.; Sunho Jeong et al., Langmuir, 2011, 27 (6), pp 3144–3149)
Authors : J. T. Carvalho, P. Grey, I. Cunha, L. Pereira, E. Fortunato, R. Martins
Affiliations : i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa and CEMOP/UNINOVA, Campus de Caparica, 2829-516 Caparica, Portugal
Resume : Recently the implementation of solution-processed or printed inorganic semiconductors, such as zinc oxide (ZnO) is becoming a real alternative in printed electronics to organic semiconductors regarding chemical stability, switching speeds and mobility. In addition, their implementation in electrolyte-gated transistors (EGTs) open the way to the development of fully-printed devices, which can operate at low voltages owing to the use of high capacitance electrolytes. The ultimate goal is to move towards ultra-cost-effective, flexible and environmentally friendly electronic devices, embracing green electronics for a sustainable environment, as demanded by modern society standards. We report the development of a fully-printed and flexible inorganic EGTs on paper substrates. The channel of the devices is based on ZnO nanoparticles blended in ethyl cellulose. The devices besides low operation voltages (-2 to 4 V), displayed n-type behavior with a subthreshold swing of 0.11 Vdec-1, a saturation mobility of 0.08 cm2 V-1s-1 and an on/off ratio of 6.70x103. Investigation in this field could potentiate effective roll-to-roll fabrication of printed logic circuits, showing huge implications for industrial printing standards. In the near future, we foresee this technology to be omnipresent in a wide range of applications, reaching from smart packaging to wearable electronics owing to the present proof-of-concept of a fully-printed inorganic EGT.
Authors : Ermelinda Falletta, Cristina Della Pina
Affiliations : Ermelinda Falletta: Department of Chemistry, University of Milan, via C. Golgi, 19-20133-Milan (Italy), CNR-ISTM, via C. Golgi 19- 20133- Milan (Italy), Cristina Della Pina: Department of Chemistry, University of Milan, via C. Golgi, 19-20133-Milan (Italy),CNR-ISTM, via C. Golgi 19- 20133- Milan (Italy)
Resume : With the discovery of electrically conductive polymers (ECPs) an attractive object of research has begun. ECPs combine the electrical properties of metals with the advantages of plastics (flexibility, lightness, stability, etc.). Among them polyaniline (PANI) is unique for its high thermal and environmental stability, ease of synthesis and interesting redox properties. The combination of electrical conductivity and tunable processability of PANI make this polymer particularly tempting for application in numerous sectors, included printing processes. Even though many methods have developed to synthesized PANI of good quality in terms of conductivity, stability and solubility, all these approaches are based on the use of toxic stoichiometric oxidants (typically metals in high oxidation state) and lead to the production of carcinogenic coproducts (i. e. benzidine). In line with the growing environmental sensitivity and the necessity of clean products, we have recently addressed our efforts on the development of environmentally friendly protocols to produce “green” PANI. Herein, we report a brief overview of the state of the art on the PANI synthesis by environmentally friendly approaches, our results in the PANI preparation by clean processes and our recent goals in their used for printable PANI-based inks fabrication. The electronic, chemical and physical properties of printed devices will be also discussed.
Authors : G. I. Márk1, K. Kertész1, G. Piszter1, I. Biró2, P. Kuzhir3, Ph. Lambin4, and L. P. Biró1
Affiliations : 1 Institute of Technical Physics and Materials Science, (MFA), Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary, http://www.nanotechnology.hu/ 2 „3D Kívánság”, 2030 Érd, Bíró u. 44/A/2, Hungary (http://3dkivansag.blog.hu/) 3 Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, 220030 Minsk, Belarus 4 Department of Physics of Matter and Radiation, University of Namur, Namur, Belgium
Resume : A single graphene layer can absorb 20% of microwave energy  and a sandwich structure of six graphene layers separated by 100 nm thick PMMA layers already absorbs 50% . Based on this fact we developed an easy to use, cheap, 3D printing process for producing complex 3D structures made from a nanocarbon-plastic composite fibre and a pure plastic (PLA) fibre. The 3D printing process makes it possible to fabricate devices with predefined BRDF (Bidirectional Reflection Distribution Function) and BTDF (Bidirectional Transmittance Distribution Function). Indeed, by applying ordered and disordered dielectric protonic crystal structures one can realize tailor-made BRDF functions , adding lossy material to the structure, however, makes it also possible to precisely define the BTDF function. We demonstrate this approach by creating an antireflection layer, which, besides its low microwave transmission minimises the reflection by introducing an appropriate nanocarbon concentration gradient. Theoretical calculations convincingly explain the measured electromagnetic absorption and transmission data in the GHz domain. 3D printing of nanocarbon containing microstructures offers a flexible and cheap technology to produce complex structures with tuneable electromagnetic characteristics, which provides a new route for microwave filters, absorbers, and sensors. 1. K. Batrakov et al, Scientific Reports 4 (2014) 7191. 2. G. I. Mark et al, PRB 80 (2009) 051903.
Authors : Yuran Kang, J.R. Binder, P.A. Gruber, O. Kraft.
Affiliations : Institute for Applied Materials(IAM), Karlsruhe Institute of Technology(KIT); Institute for Applied Materials(IAM), Karlsruhe Institute of Technology(KIT); Institute for Applied Materials(IAM), Karlsruhe Institute of Technology(KIT); Institute for Applied Materials(IAM), Karlsruhe Institute of Technology(KIT).
Resume : With the popularity of flexible electronics, applications of stretchable or wearable devices require advanced electronic materials, which exhibit excellent mechanical robustness and electronic functionality at high strains. This is of special interest for the fabrication of conductive tracks, which are used as interconnects for such devices. One of the most significant hurdles to achieving stretchable conductive tracks using conventional materials , e.g. metallic nano-structures, arise from their intrinsic limitations like poor mechanical stretchability. As an alternative, carbon nanotubes (CNTs) offer outstanding electrical and mechanical properties. Especially, when CNTs are deposited as thin films, they provide superior mechanical stretchability. In addition, CNTs can be formulated as inks and adapted for different printing processes, e.g. inkjet printing. In our study, we fabricated conductive tracks, composed of monolithically inkjet-patterned CNT films on polymer substrates, and we investigated the relationship between printing process, film morphology and their electro-mechanical properties. Experimental results have shown that, those films offer excellent mechanical and electrical properties. They show excellent mechanical stretchability up to 50% of tensile strain without significantly degrading their electrical performance, and outstanding mechanical durability up to 1 million cycles at a strain amplitude of 2%. Those promising properties of CNT-based conductive tracks will benefit the production of high-performance stretchable electronic devices.
Authors : Pei He, Brian Derby
Affiliations : School of Materials, University of Manchester, Manchester, United Kingdom
Resume : Inkjet printing is a promising manufacturing route for the production of large area and low cost flexible electronics. Recently, graphene, which is a monolayer of sp2-bonded carbon, has been considered as a potential candidate to replace metallic conductors in printed devices due to its remarkable mechanical, electrical properties. Graphene inks based on pristine graphene flakes or reduced graphene oxide (rGO) formed by liquid phase exfoliation (LPE) have been printed for electronic applications, such as transistors, conductive electrodes, chemical sensors, and radio frequency devices. However, the size of graphene or rGO by LPE method in previous work is in a relatively small mean graphene flake size, typically < 1 µm. Such small flake size will increase the number of inter-flake junctions in any conductive pathway, which will reduce the conductivity of a printed graphene film to below that of CVD grown graphene or of mechanically exfoliated graphene sheets. Here, we present a holistic approach to produce highly conductive printed rGO patterns through oxidization of graphite, liquid exfoliation of graphite oxide (GO), ink formulation, inkjet printing, and final reduction. We have produced large GO sheets with diameter up to 200 µm using the improved Hummers method. Such large size GO sheets can be successfully ejected to form stable droplets through a 60 µm nozzle, which is significantly smaller than the largest GO flakes in the ink. These large flake inks can be used to print stable linear and 2D features after drying. After reduction, the rGO pattern shows conductivity as high as 2.51 × 10^4 S/m for processing temperature lower than 100 °C. In addition, we produced a fully printed flexible humidity sensor by using rGO as the electrode and GO as the sensor layer on plastic substrate.
Authors : S. A. Hodge, P. G. Karagiannidis, F. Tomarchio, A. O. R. Raji, N. Decorde, L. Lombardi, F. Torrisi, A. C. Ferrari
Affiliations : Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK
Resume : The conductive ink and paste business is a large market that is expected to grow to $2.87 billion by 2025,1 comprising nanometal inks (silver, copper), conductive polymers and carbon-based inks. Nanometal inks are high cost2 (silver: $550/kg; copper: $7.4/kg on average during 2014), requiring high temperature sintering to remove polymeric stabilizers,3 and have high specific gravity which leads to reduced stability upon storage.3 Nanometals also suffer long-term oxidation.4 Conductive polymer inks are limited by their solubility, stability, and processability.3 Graphene, however, can be exfoliated5-7 from highly abundant, low cost2 graphite ($1.5-2/kg on average during 2014).Furthermore, the electrical, mechanical and thermal properties of graphene combined with its high surface area,7 make it highly desirable for electrodes in energy storage devices.8Here, we use a scalable microfluidic processing route to exfoliate graphite in water-surfactant solutions. Graphene nanoplatelets (GNPs) with lateral size ~1 µm and thickness ~10 nm, are produced at loadings >50 mg/mL. These are significantly higher than current graphene production routes (sonication5 or shear mixing9) that afford low concentrations of few layer graphenes (<0.1 mg/mL) following additional centrifugation steps to remove the non-exfoliated particles.5,9The ink rheology is tuned using sodium carboxymethyl cellulose over the range of 1 1800 cP, so that roll-to-roll flexographic and screen printing can be achieved. The high GNP loading affords high conductivities when printed(~2.2 Ω/□ @ 25 µm thickness; 2 x 104 S/m), essential for fast charge/discharge rates in energy storage devices.8 In this context, we demonstrate screen and flexographic printed electrodes on plastic for flexible supercapacitors with an areal capacitance of 10 mF/cm2 with 5 µm thick electrodes, comparable to state of the art flexible planar supercapacitor electrodes.10  K. Ghaffarzadeh and H. Zervos, Conductive Ink Markets 2015-2025: Forecasts, Technologies, Players. IDTechEx, 2016  US Department of the Interior and US Geological Survey, Mineral Commodity Summaries 2015  A. Pekarovicova, Recent Advances in Electrical Engineering and Computer Science, 13-21 (2015)  S. Magdassi et al. Materials, 3,4626-4638, (2010)  Y|. Hernandez et al. Nature Nanotechnol.3, 563-568 (2008)  F. Bonacorso et al. Materials Today, 15, 12, 564, (2012)  A. C. Ferrari et al. Nanoscale7, 4598 (2015)  F. Bonacorso et al. Science, 347, 6217, (2015)  K. R. Paton et al. Nature Materials 13, 624 (2014)  Y. Shao et al. Chem. Soc. Rev.,44, 3639-3665 (2015)
Poster Session : -
Authors : Tomi Hassinen, Ari Alastalo, Kim Eiroma, Tiia-Maria Tenhunen, Vesa Kunnari, Timo Kaljunen, Ulla Forsström and Tekla Tammelin
Affiliations : VTT Technical Research Centre of Finland, Tietotie 3, Espoo, FI-02044 Finland
Resume : We report fully-printed top-gate-bottom-contact organic thin-film transistors using substrates prepared from cellulose nanofibers and commercially available printing inks to fabricate the devices. Gravure printing was used to coat the substrate with a polymer resist to decrease the surface roughness and close the surface. Transistor structures were fabricated using inkjet printing for metal-based conductors and gravure printing for the polymer-based dielectric and semiconducting layers. The maximum processing temperature was 120 °C. The obtained transistor performance is compared to that of similar sheet-to-sheet and roll-to-roll printed transistors on plastic substrate in terms of mobility, threshold voltage, on/off ratio, and bias stress stability.
Authors : Changhun Yun (1), Jungmin Choi (2), and Seunghyup Yoo (2)
Affiliations : 1. Center for Nano-Photonics Convergence Technology, Korea Institute of Industrial Technology, Gwangju 500-480, Korea 2. Department of Electrical Engineering, Korea Advanced Institute of Science of Technology, Daejeon 305-701, Korea
Resume : We realize on the advanced control of straightforward fabrication of an organic thin-film pattern using digitally-controllable organic vapor-jet printing (D-OVJP) method, in which deposition of organic materials is controlled point by point in a digital manner by producing a jet of organic vapor in a pulsed mode only on demand. The D-OVJP can utilize all the benefits of the current OVJP technology which combines the advantages of both (i) a conventional evaporation method such as use of well-established, sublime-grade small molecules resulting in high performance and long-term reliability and (ii) ink-jet printing technology such as mask-less pattern formation and a good scalability. In D-OVJP system, the “jet-on-demand” type operation can be possible in a straightforward manner through the change of input digital signals, implying the number of the pulses and/or to the duty ratio of the digital signal. By utilizing the full advantages of D-OVJP method, the point-by-point control of conductivity of doped organic semiconductors can be realized, which can give an enhanced performance of printed electronic devices with organic materials. We will also present some device applications based on the localized control of the concentration of dopant molecules at the co-deposition system by using D-OVJP method.
Authors : Jangwhan Cho, Wook hyun Cho, Dae Sung Chung
Affiliations : School of Chemical Engineering and Material Science, Chung-Ang University Jangwhan Cho; Wook hyun Cho; Dae Sung Chung
Resume : We suggest a novel method of fabricating water-borne colloids of semiconducting polymers for use in environmentally benign processes involving organic electronics, without compromising the high charge carrier mobility of the polymeric semiconductors. Non-ionic surfactants were utilized as a key material to fabricate aqueous colloids of semiconducting polymers via a miniemulsion process. By developing smart surfactant engineering techniques, we could selectively remove non-ionic surfactants after film deposition, rendering efficient inter-particle charge coupling. We introduced such non-ionic surfactants-technique onto a donor-acceptor type polymeric semiconductor with an inherently high charge carrier mobility, resulting in a high-mobility (~2.51 cm2/ V s) water-borne polymer field effect transistor for the first time
Authors : Chuan-Ying Wang * and Chien-Neng Liao
Affiliations : Department of Materials Science and Engineering, National Tsing-Hua University
Resume : Metallic nanowires (NWs) such as silver and copper NWs have been dispersed on polymer substrates serving as transparent conductive films to replace the predominant indium tin oxide (ITO) films in flexible electronic devices. Although Cu NWs have desired cost advantage, oxidation is the detrimental issue associated with Cu NW fabrication process. It was hypothesized that the oxidation resistance could be improved by coating an inert metal on Cu NWs to form an oxidation barrier layer. In this study we intend to improve both oxidation resistance and mechanical strength through introducing dense nanoscale twinning structure in cupronickel NWs. First, nanotwinned Cu NWs were synthesized using porous anodic aluminum oxide (AAO) templates by pulsed electroplating. After the nanotwinned Cu NWs were released from AAO templates by a wet chemical method, they were coated a thin layer of Ni using a low-toxicity reducing agent, sodium borohydride, in ethylene glycol solvent. A microstructural and compositional analysis has been conducted on the cupronickel core-shell structure by transmission electron microscopy. The temperature-dependent oxidation characteristics of single cupronickel NW was investigated by monitoring the evolution of electrical resistivity in ambient using a 4-point method. Moreover, the cupronickel NWs were embedded into PMMA through vacuum filtration method and pressing process. The NW contact resistance is greatly improved by the pressing process. The NW embedded transparent film has achieved a low sheet resistance of 16 Ohm/sq. The study shall help the development of low-cost transparent conductive films using Cu-based NWs.
Authors : Shishkovsky I., Scherbakov V., Kuznetsov M.
Affiliations : Shishkovsky I. and Scherbakov V - Lebedev Physical Institute (LPI) of Russian Academy of Sciences, Samara branch, Novo-Sadovaja st. 221, 443011 Samara, Russia; Kuznetsov M. - All-Russian Research Institute on Problems of Civil Defense and Emergencies of Emergency Control Ministry of Russia (EMERCOM), 7 Davidkovskaya Str., Moscow, 121353 Russia.
Resume : In this study, we report about the laser synthesis and characterization of the gradient core–shell HTS covered with polycarbonate and/or polyesterketone shells of ultra-fine particles and layerwise selective laser melting of the 3D samples. The optimal regimes of such synthesis are being discussed. Optical and scan electron microscopy with EDX, X-ray diffraction studies show that both core–shell systems have a complex structure with interesting electro-physical properties. Expanding computer aid design of the SHTC core distribution in polymer matrix opens door to manipulate of electromagnetic field distribution within such 3D complex core-shell samples. Keywords: selective laser melting (SLM); high temperature superconductivity (HTS), core-shell structures, polycarbonate, polyesterketone.
Authors : Simone Quaranta, Krishna Naishadham, Aamer Abbas Khan, Mauro Giorcelli, , Patrizia Savi
Affiliations : Simone Quaranta UOIT (University of Ontario Institute of Technology) Faculty of Science, Oshawa, ON, Canada; Krishna Naishadham School of ECE, Georgia Institute of Technology, Atlanta, GA, United States; Aamer Abbas Khan Dept. of Applied Science and Technology (DISAT), Politecnico di Torino, Torino, Italy; Mauro Giorcelli Dept. of Applied Science and Technology (DISAT), Politecnico di Torino, Torino, Italy; Patrizia Savi Dept. of Electronic and Telecommunications (DET), Politecnico di Torino, Torino, Italy
Resume : Carbon nanotubes (CNTs) constitute a unique class of materials with a wide range of applications. The sp2 chemical bonding of carbon atoms provides exceptional electronic, thermal and mechanical properties [1, 2]. With proper solvent, surfactant or stabilizer chemistry, CNTs can be dispersed with different binders to produce inks that can be used with various printing methods (screen printing, aerosol jet printing, transfer printing, contact printing) . Screen printing offers a fast, economic and potentially large scale method for the deposition of carbon nanostructures on a wide range of substrates. This technique is already used for the deposition of conductive, resistive and dielectric layers in the fields of photovoltaics, hybrid integrated circuits, energy storage, automotive and electrochemical sensors . In this work, screen printed multi-walled carbon nanotubes (MWCNTs) are deposited as thick films by forcing a high viscosity ink through a 2.5x2.5 (mm) open area on a 90 T polyester mesh with a squeegee . The rheological and dielectric properties of the films have been modulated through different combinations of binders, solvents, inks? additives and MWCNT concentration. MWCNT powders, inks and films are characterized by FESEM, Raman spectroscopy, thermal analysis, and sheet resistance measurements. Thick films comprising different types of MWCNTs are integrated in printed patch antennas and slot ring resonators fabricated on commercial substrates (FR4, Arlon) to investigate the tuning of their resonances at microwave frequencies. It is observed that the MWCNT films essentially present a constant surface resistance (or conductivity) but a varying capacitive reactance that is responsible for tuning the circuit or antenna in which the film is embedded. The ring resonator exhibits higher sensitivity to tuning in the WLAN band (2.4 GHz) than the patch antenna which is resonant in the X-band (8 GHz). Results from electromagnetic simulations as well as microwave measurements will be presented at the conference. References  H. Dai, ?Carbon Nanotubes:Synthesis, Integration and Properties,? Accounts of Chemical Research, vol. 35, no.12, pp.1035-1044, 2002.  T.E. Chang, A. Kisliuk, S.M. Rhodes, W.J. Brittain, A.P. Sokolov, ?Conductivity and mechanical properties of well-dispersed single-wall carbon nanotube/polystyrene composites,? Polymer, vol. 47, pp. 7740-7746, 2006.  C.S. Jones, X. Lu, M. Renn, M. Stroder, W.-S. Shih, ?Aerosol-jet-printed, high-speed, flexible thin-film transistor made using single-walled carbon nanotube solution,? Microelectron. Eng., vol. 87, pp. 434-437, 2010.  X. Cao, H. Chen, X. Gu, B. Liu, W. Wang, Y. Cao, F. Wu and C. Zhou, ?Screen Printing as a Scalable and Low-Cost Approach for Rigid and Flexible Thin-Film Transistors Using Separated Carbon Nanotubes,? ACS Nano, vol. 8, no. 12, pp. 12769-12776, 2014.  Y. Zhou, L. Hu, G. Grüner, ?A method of printing carbon nanotube thin films,? Appl. Phys. Lett. , vol. 88, pp. 109-123, 2006.
Authors : David A. Gregory (1), Yu Zhang (1), Patrick J. Smith (2), Xiubo Zhao (1), Stephen J. Ebbens (1)
Affiliations : (1) Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, S1 3JD, UK (2) Department of Mechanical Engineering, University of Sheffield, Mappin Street, S1 3JD, UK
Resume : A novel approach of using layer by layer reactive inkjet printing of regenerated silk fibrin was used to generate micron-sized silk rockets which have the enzyme catalase immobilised inside the scaffold structure and use catalase to drive their motion in samples containing H2O2. We show that it is possible to digitally define the enzyme distribution within the rockets and alter their trajectory behaviour accordingly. This technique has great potential to easily incorporate different enzymes, proteins, chemicals or other biomolecules and build versatile devices. Small scale devices that can generate thrust via catalytic reactions within fluidic environments have potential applications including environmental monitoring and remediation, in vivo drug delivery and repair, and lab on a chip diagnostics. Current manufacturing processes of such devices often use slow and lengthy production processes (e.g. evaporation) combined with expensive materials such as platinum. The location of catalyst on these devices has been shown to influence trajectory behaviour but is not easy to control using conventional methods. Devices using e.g. platinum as a catalyst can undergo biofouling thus inhibiting their catalytic reaction. By using biocompatible silk scaffolds created by reactive inkjet printing the devices generated have the potential to overcome all these problems.
Authors : Nimmakayala V. V. Subbarao, Murali Gedda, Parameswar K. Iyer and Dipak K. Goswami
Affiliations : Center for Nanotechnology, Department of Chemistry, Indian Institute of Technology Guwahati, Assam-781039, Indian Institute of Technology Kharagpur, Department of Physics, Kharagpur ? 721302, India
Resume : Fabrications of organic field-effect transistors (OFETs) based sensors have attracted immense attention for monitoring health and wellness parameters and other medical applications due to the capability to easily integrate into the main electronics with multi-parameters analysis to derive the physiological parameters of interests. In addition, such devices can be fabricated on transparent, stretchable and ultra flexible substrates for large area measurements. In this work, we are going to present how the polarization of gate dielectric layer can be exploited to fabricate temperature sensors, which is highly sensitive to temperature within ?30oC to 80oC. Tri-layer dielectric system of PMMA/PVA/Al2O3 was used for the fabrication of CuPc based OFETs. PVA layer is polar (contain ?OH groups) and highly sensitive to ambient condition. This layer has been sandwiched between hydrophobic PMMA and anodized Al2O3 layer to protect degradation of PVA layer in ambient. Polarization of ¬?OH groups was found to be highly sensitive to temperature, which was exploited to fabrication of temperature sensors using OFETs. In addition, we have demonstrated remarkable enhancement of OFET performances under ambient condition [1,2]. The observed temperature range is going to be suitable to found application in monitoring body measurement, temperature for chemicals and vaccine, or transporting medicine and organs etc. The devices were also fabricated on flexible substrates and were found to be suitable in flexible applications. References:  Enhanced Environmental Stability Induced by Effective Polarization of a Polar Dielectric Layer in a Trilayer Dielectric System of Organic Field-Effect Transistors: A Quantitative Study, Nimmakayala V. V. Subbarao, Murali Gedda, Parameswar K. Iyer and Dipak K. Goswami, ACS Appl. Mater. Interfaces, 7 (2015) 1915?1924  Organic Field-Effect Transistors as High Performance Humidity Sensors with Rapid Response, Recovery Time and Remarkable Ambient Stability, Nimmakayala V. V. Subbarao, Murali Gedda, Parameswar K. Iyer and Dipak K. Goswami, Organic Electronics (2016)
Authors : Baekhoon Seong, Hyunsung Park, Ilkyeong Chae, Hyung-Seok Jang, Liwei Lin, Doyoung Byun
Affiliations : Department of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-Ro, Jangan-Gu, Suwon, Gyeonggi 440-746, Republic of Korea (Baekhoon Seong; Ilkyeong Chae; Doyoung Byun) Department of Mechanical Engineering, University of California at Berkeley, Berkeley, 94720, United States (Hyunsung Park; Hyung-Seok Jang; Liwei Lin)
Resume : We investigated the deposition of a silver nanowire (Ag NW) ring generated by being encapsulated inside fine droplets. The regime of the droplet size required to transform the Ag NWs into a ring shape was determined. The electrostatically spray method was used to ensure the generation of fine droplets with a size in the necessary regime for the ring formation. Coiled NW rings were obtained by utilizing the force equilibrium of the NW’s axial stress and the droplet surface tension. When the NW’s axial stress was greater than the pressure change across the droplet surface due to the surface tension, a NW inside a droplet was observed in the form of a coiled ring along the rims of the droplet.
Authors : Sunghoon Jung, Won-min Ahn, Do-Geun Kim
Affiliations : Korea Institute of Materials Science
Resume : Recently, the issues of flexible transparent electrode (TE) have attracted a great of attention as the interests in flexible opto-electronics. Indium-tin-oxide is one of the most representative materials as TE, however, its brittleness is a major bottleneck for applying to flexible electronics. For replacement of ITO, many alternative materials such as other metal oxide, graphene and carbon nanotube have been studied. Among the alternatives, a random network of silver nanowires is a viable candidate for replacing ITO because of highly optical transparency, electrical conductivity and mechanical flexibility. Although the great potentials of silver nanowire as TE, unstable thermal and environmental properties of silver nanowire have been prevented commercialization. In this study, we applied plasma technology to silver nanowire TE. Ultrathin film grown on the silver nanowire deposited by plasma process enhance the thermal and environmental stabilities as well as electrical properties without the losses of optical transparency. The hybrid silver nanowire could endure more than 200 Celsius degree of temperature, advance 100% for corrosion resistance compared to pristine silver nanowire transparent electrode. Transparent heater based on the hybrid silver nanowire showed improved lifetime and maximum operation temperature.
Authors : R Barras, I Cunha, L Pereira, E Fortunato and R Martins
Affiliations : i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa and CEMOP/UNINOVA, Campus de Caparica, 2829-516 Caparica, Portugal
Resume : Thick and narrow conductive flexible electrodes were printed on a multilayer coated paper substrate using an electroconductive functional ink, which was designed and formulated for screen-printing. The inks were prepared using simple, non-expensive and eco-friendly materials by blending carbon fibers (CFs) into the matrix of a water-soluble cellulose derivative, such as carboxymethyl cellulose (CMC). For low concentration of CFs (10 wt.%), the printed films exhibit an average resistivity of 4.69 ± 0.95 ?cm , after 10 printing steps and without any post-printing annealing process. After 6 months the ink remained stable and the printed films kept their initial resistance. When bended the resistivity decreases under compressive strain while an abrupt loss on conduction was observed under tensile strain. After 1000 bending cycles, a reduction of the resistivity was observed on the printed films in the flat conditions. The developed ink was successfully used in a fully-screen-printed electric circuit.
Authors : Sureeporn Uttiya,Cristina Bernini,Maurizio Vignolo,Daniele Marré,Antonio Sergio Siri,Luca Pellegrino
Affiliations : Physics Department, University of Genoa, Genoa (Italy);CNR-SPIN, Genoa (Italy)
Resume : Over the last decade, drop-on-demand inkjet printing has drawn very much interest from printing text or graphics to scientific research . Inkjet printing is precise, quick and inexpensive. Hence it is a good candidate for conductive metallic pattern fabrication. Inks must be manufactured to be suited with the rheological requirements of fluid flow deposited on the proper substrates. Inks are exploited in two different approaches such metallic nanoparticles suspensions, that consist of metal organic precursors in appropriate solvents [2-4] and metal organic decomposition, which is synthesized from metallic salt and formed in true solution [5-6]. Herein, we report a study on a simple, economic and low-toxic fabrication route of conductive silver patterns obtained from aqueous ink solutions of silver nitrate (AgNO3) . AgNO3 patterns were printed on flexible polyimide (PI) substrates from 3M of AgNO3 aqueous inks using a DMP 2831 Dimatix-Fujifilm apparatus. To increase the adhesive force between the printed patterns and PI, an extreme small amount of dishwashing detergent of about 0.0025 % (v/v) was added into the ink to act as surfactant, along with oxygen plasma etching treatment. Conductive Ag patterns were achieved via thermal annealing at about 250 °C under argon-5% hydrogen gas flow. We report a systematic analysis of the printed patterns in terms of their morphology and behavior of electrical resistivity as a function of temperature in the 4.2 K to 300 K range.
Authors : Christian Speyerer1, Achim Weber1-2
Affiliations : 1 University Stuttgart, Institute of Interfacial Process Engineering and Plasma Technology IGVP, Nobelstr. 12, 70569 Stuttgart, Germany; 2 Fraunhofer Institute for Interfacial Engineering and Biotechnology, Stuttgart, Germany.
Resume : Electro photography (laser printing) has emerged to one of the leading print technologies during the last decades. The xerographic process enables the simultaneous two dimensional alignment of multiple toner materials with high spatial resolution (600 dpi, resolution <100 μm). Due to its solvent-free character, a high solid content can be transferred in a single printing cycle, offering the possibility for a quick layer-by-layer construction of three-dimensional objects.  However, the conventional melting process prohibits accurate structure building and in contrast to the well-established ink jet process, three-dimensional electro photography has not yet been examined for the assembly of biofunctional materials. Especially the cytotoxicity of common toner components as well as the requirement of high temperatures during the conventional curing procedure have prevented the approach towards this interesting application. Therefore, a new biocompatible class of organic-inorganic composite particles has been developed to be processed as toners at low temperatures using common laser printing techniques.  In this paper, we provide a detailed kinetic investigation about the controlled surface functionalization of acrylic particles in respect to the hydrolysis time, temperature and the sodium hydroxide concentration. Furthermore, we have studied the subsequent carbodiimide mediated coupling of numerous functional amines onto the generated carboxylic group.
Authors : Himadri S. Majumdar, Jaakko Leppäniemi, Olli-Heikki Huttunen, Kim Eiroma and Ari Alastalo
Affiliations : Printed Functional Solutions, VTT Technical Research Centre of Finland, Espoo/Oulu, Finland
Resume : In this paper, we summarise our latest research on printed metal oxide transistors on flexible substrates. By using conventional printing processes such as sheet-fed inkjet printing  or rotary flexographic printing , In-nitrate-based precursor inks can be deposited on substrates and converted via annealing into thin, high-quality In2O3 semiconductor films for thin-film transistor (TFT) applications. The required temperature budget for the precursor to metal-oxide conversion can be reduced from ~300 °C down to 180 °C using far ultraviolet light-assisted (FUV) annealing method . The thickness of the printed semiconductor layer critically affects the TFT device performance, such as the saturation mobility (µsat) and turn-on voltage (Von). The increase in the film thickness leads into a shift in the device operation from enhancement- to depletion-mode which can be exploited in depletion-load NMOS inverters that allow high gains . References:  J. Leppäniemi, K. Eiroma, H. S. Majumdar, A. Alastalo, In2O3 Thin-Film Transistors via Inkjet Printing for Depletion-Load NMOS Inverters, IEEE Electron Dev. Lett., accepted  J. Leppäniemi, O.-H. Huttunen, H. Majumdar, A. Alastalo, Flexography-Printed In2O3 Semiconductor Layers for High-Mobility Thin-Film Transistors on Flexible Plastic Substrate, Adv. Mater. 2015, 27, 7168-7175  Appl. Phys. Lett. 2014, 105, 113514
Authors : K. Rajan,1,2 S. Bocchini,1 A. Chiappone,1 I. Roppolo,1 D. Perrone,1 M. Castellino,1 K. Bejtka,1 C. Ricciardi,2 C.F. Pirri,1,2 and A. Chiolerio1
Affiliations : 1Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento, 21, 10129, Torino, Italy. 2Applied Science and Technology Department, Politecnico Di Torino, C.so Duca degli Abruzzi 24, 10129, Torino, Italy.
Resume : In the present study, a Resistive Switching Device (RSD) is fabricated by means of inkjet printing. The pristine device shows different switching behaviors according to printed patterns, one being a stable unipolar switching with an on/off ratio of 104. Ageing of RSD is investigated with XPS, which confirmed the oxidation of the silver nanoparticles, leading to a decrease in the on state conductivity of the RSD. The second behavior corresponds to a write-once-read-many effect. The present study gives an insight into the field induced formation of conductive silver filament, which gives rise to a transition in the resistance. The active switching matrix used in the present case serves as a good ink for an easy deposition onto various substrates thus widening its scope in various fields of printed electronics. 1. Y. Ji, B. Cho, S. Song, M. Choe, T.W. Kim, J.S. Kim, B.S. Choi, T. Lee. Unipolar Bistable Switching of Organic Non-Volatile Memory Devices with Poly(styrene-co-styrenesulfonic acid Na). Journal of Nanoscience and Nanotechnology, 11, 2011, 1385-1388. 2. S. Moller, C. Perlov, W. Jackson, C. Taussig, S.R. Forrest. A polymer /semiconductor write-once-read-many-times memory. Nature, 426, 2003,166-169. 3. E.J Sandouk, J.K. Gimzewski, A.Z. Stieg. Multistate resistive switching in silver nanoparticle films. Sceince and Technology of Advanced Materials, 16(4), 2015. 4. Nanotechnology, Science and Applications, 9, 2015, 1-13.
Authors : E.M. Khairullina,A.V. Smikhovskaia,S.V. Safonov,I.I. Tumkin,M.S. Panov,S.S. Ermakov,V.A. Kochemirovsky
Affiliations : 1Saint Petersburg State University, St.Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia
Resume : The detection of glucose and hydrogen peroxide is a critical analytical goal due to its importance for many fields of science and industry. Despite the fact enzyme sensors are successfully used in clinical practice and produced on industrial scale, they have a number of disadvantages such as high oxygen dependency, low temporal and thermal stability. Alternative to enzyme sensors is the non-enzymatic ones. Researches are shown the promising electrodes have surface with nano-sized feature, because it facilitates the charge transfer and prevents the molecule denaturation. This work presents one-step approach for the fabrication of Cu, Cu-Au and Ni nanostructures electrodes by laser deposition technique. Topology was investigated with the use of a SEM, XRD and EDX. Electrocatalytic activity of sensor platforms towards hydrogen peroxide and glucose was investigated by cyclic voltammetry and amperometry. Cu electrode showed the highest activity, it has a linear dependence of the current-concentration in the range of 10-100 μmol/L for H2O2 and 0.6-3.0 mmol/L for glucose. Research was performed at Educational Resource Center of Chemistry, Center for Geo-Environmental Research and Modeling and Center for X-ray Diffraction Methods of SPSU Research park. Study was funded by RFBR (16-33-00645) and SPSU (126.96.36.1995).
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