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Materials for energy and environment

B

Advanced functional materials for environmental monitoring and applications

About three quarters of the European population lives in urban areas. The urban environment has a profound effect on people’s health and well-being. Environmental sustainability of the urban society is a key issue in the era of smart cities and information services for the quality of life. Solid state sensors based on functional materials have been developed for several decades and recent improvements in nanotechnology and multifunctional materials have open up the possibility to develop a new generation of sensitive, selective and stable sensors, with largely improved capacity to give relevant information both on a personal level and system levels.

 

Scope:

 

Air quality takes a prominent position in discussions on urban environment and health, and it is a concern for many inhabitants of urban areas. Nanotechnologies including nanostructured materials for sensing, chemical sensors, portable systems and commercial devices give a challenging opportunity to create a new generation of nanosensors for air quality control. Functional nanomaterials (i.e., nanowires, nanotubes, graphene, nanoparticles of metal-oxides, carbonnanostructures, large band-gap semiconductors, and metals) with new sensing properties (detection at ppb-level, high sensitivity and selectivity), self-heating and durable operations for low powered (tens of mWatt to tens of mWatt) devices are potential key elements in advanced air quality measurements for indoor and outdoor air quality monitoring.

 

Modeling provides a tool for nanomaterials tailor-made for specific purposes and applications. In order to realize functional, sensor-systems improvements in packaging, testing and aging are also very important and a focus area of this conference as current research hot-issues.

 

Nanotechnologies offer a big challenge to create innovative low-cost nanosensors for air quality monitoring. Functional nanomaterials (one- and two-dimensional nanostructures of carbon, graphene, metal-oxides, metals, polymers, supramolecular materials, self-organized materials, organic/inorganic materials, hybrid composites) with new tailored properties are key-issues for the development of low-powered devices for indoor and outdoor air quality monitoring, including practical applications such as geo-tagged database collected by networked stationary or mobile smart devices to address new sensing concepts for novel air quality monitoring and mapping techniques of gas molecules and particulate matter. These solid-state chemical sensors based on smart materials are useful for real deployment and complementary to the existing official high-cost high-quality air-quality monitoring stations used by public authorities, scientists or community groups.

 

Many worldwide investigators are involved in research in materials physics/chemistry and engineering, including nanosciences and nanotechnologies for sensing applications. Current international research includes the design and synthesis of organic, inorganic, polymers, and hybrid materials, the development of biomimetic materials and biomaterials, the discovery of new organometallic catalysts, the synthesis of nano- and mesoscopic materials including raw materials, the preparation of multilayers and multifunctional coatings, the study of chemistry of surfaces and interfaces, the exploration of the sensing properties of reactive materials, the characterization of the matter at nanoscale level for deep insights, the photo-physical study of supramolecular materials and the demonstration of functional nano/micro systems.

 

Basic research on sensing mechanisms and gas/surface interaction is critical for advancements in materials science and nanosensors in order to address practical applications in the field of the environmental monitoring, safety, security, healthcare, automation, green buildings, energy efficiency, transportations, food quality, industrial process control.

 

Hot topics to be covered by the symposium:

 

The specific technological areas are:

 

  • Advanced gas sensing semiconducting materials
  • Hybrid materials and nanocomposites for gas sensing
  • Catalytic sensing materials
  • Device fabrication, packaging, testing and aging
  • New (nano)sensors for monitoring gaseous and liquid pollutants
  • Ab initio modeling of gas/surface interaction
  • Surface-sensitive spectroscopies for studying sensor/gas interaction
  • Modeling of materials, devices and sensor systems
  • Functional applications

 

Publication:

 

Proceedings as Regular Research Papers will be managed by a peer-review process in a Special Issue to be published in Journal of Sensors and Sensor Systems (JSSS) edited by Copernicus Publications.

 

Deadline for submission to Special Issue JSSS: 30 June 2014
Publication of Special Issue JSSS expected on December 2014

 

Manuscripts must be submitted on‐line via the JSSS Manuscript Submission, see: http://www.journal-of-sensors-and-sensor-systems.net/submission/manuscript_submission.html

 

For manuscript preparation and submission, please follow the guidelines and template in the Information for Authors at the JSSS Journal webpage: http://www.journal-of-sensors-and-sensor-systems.net/submission/manuscript_preparation.html

 

Further information on Special Issue JSSS: Dr. Michele Penza, ENEA, Brindisi, Italy: michele.penza@enea.it

 

Sponsors:

 

 

  2mstrumenti_logo
  alphasense 
   ethera-logo
  senseair_sensorsforlife
  sgx-logo 
  ust-logo1 

 

Symposium organizers:

 

Michele Penza
ENEA Italian National Agency for New Sensing Technologies
Energy and Sustainable Economic Development
PO BOX 51 Br-4
I-72100 Brindisi
Italy
Phone: +39 0831 201422
Fax: +39 0831 201423
michele.penza@enea.it

 

Anita Lloyd Spetz
Linköping University/Oulu University
Dept. Physics, Chemistry and Biology
Linköping University
SE-581 83 Linköping
Sweden
Phone: +46 13 281710; (Finland): +358 294 482717
Fax: +46 13 137568
spetz@ifm.liu.se

 

Albert Romano-Rodriguez
University of Barcelona
Departament d’Electrònica
Martí i Franquès 1
08028 Barcelona
Spain
Phone: +34 93 4039156
Fax: +34 93 4021148
aromano@el.ub.es

 

Yongxiang Li
Shanghai Institute of Ceramics
Chinese Academy of Sciences
No.1295 Dingxi Road
Shanghai
China
Phone: +86 21 52411066
Fax: +86 21 52413122
yxli@mail.sic.ac.cn

Meyya Meyyappan
NASA
Ames Research Center
MS 229-3
Moffett Field, CA 94035
USA
Phone: +1 650 604 2616
m.meyyappan@nasa.gov

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Nanostructured Metal Oxides Chemical Sensors II : Jyrki Lappalainen, University of Oulu (Finland) and Gemma Garcia-Mandayo, CEIT (Spain)
10:30
Authors : F.E. Annanouch, J.L. Ramírez, M. Camara*, D. Briand* and E. Llobet
Affiliations : MINOS-EMaS, Universitat Rovira i Virgili, Tarragona, Spain *EPFL, Samlab, Neuchatel, Switzerland

Resume : Aerosol assisted CVD, as shown by our prior results [1], is a flexible, inexpensive and high-yield technique for growing metal oxides with remarkable gas sensing properties. Here we show that this technique is suitable for growing metal-decorated low-dimensional metal oxides directly on flexible polymeric hotplates. This represents a significant breakthrough towards mass-market affordable nanotechnology-based gas sensors, taking into account integration easiness and a great reduction in production cost. Au or Pt nanoparticle decorated tungsten oxide nanowire (5 microns long and 60 to 120 nm wide) films were grown at 380ºC by AA-CVD directly on the electrode area of polymeric hotplates using tungsten hexacarbonyl, hydrogen tetrachloroaurate and hydrogen hexachloroplatinate as precursors. On the other hand, porous nanoparticle films of pure tungsten oxide were obtained under the same conditions. The response to hydrogen of the different sensors was tested at different operating temperatures (200 to 350ºC). The optimal operating temperature was found to be 300ºC. Pt-decorated tungsten oxide NWs (followed by Au-WO3 NWs) showed the highest response to hydrogen with over an order of magnitude decrease in resistance when exposed to 500 ppm of H2. Pure tungsten oxide NP films exhibited weak response to hydrogen. At the conference, morphological and compositional studies together with humidity effect will be presented and discussed in detail. [1] Adv. Funct. Mat. 23 (2013) 1313-1322.

B.B.II.1
11:00
Authors : C. Baratto*, Raj Kumar*, G. Faglia*, G. Sberveglieri*, K.Vojisavljevic**, B.Malic**
Affiliations : * CNR-INO SENSOR Lab. and University of Brescia, Dept. of Information Engineering, Via Valotti, 9 25133 Brescia, Italy ** Electronic Ceramics Department, Jozef Stefan Institute Jamova 39, SI-1000, Ljubljana, Slovenia

Resume : Recently, new ternary material with p-type behavior attracted significant research interest in the field of chemical gas sensing, since they can be teamed with well-known n-type materials to be use in a sensing matrix like an electronic nose. Copper aluminum oxide is a p-type ternary oxide that raised interest as a transparent conducting material in the delafossite phase CuAlO2; we demonstrated that different phases with higher resistance can be applied successfully as p-type resistive gas sensor for ozone detection. Copper aluminum oxide thin films were deposited by RF sputtering in inert atmosphere starting with a delafossite CuAlO2 target. Thin films with different morphology and phases were obtained by changing the deposition temperature and post annealing treatment: in some cases polycrystalline nanowires were observed on silicon substrate. Thin films were tested for ozone, NO2 and reducing gas (CO, ethanol, acetone) sensing in the working temperature range from 200-500°C. Two order of magnitude sensor response towards 70 ppb of ozone was observed at 300°C. Response to reducing gases was much smaller than that to ozone and optimum working temperature was observed at 400°C. Sensing capabilities will be discussed in relation to thin film morphology and phases analyzed by SEM, Raman spectroscopy and XRD. The research leading to these results has received funding from the European Communities 7th Framework Programme under the grant agreement NMP3-LA-2010-246334, ‘‘ORAMA’’.

B.B.II.2
 
Graphene Chemical Sensors I : Jérôme Brunet, Université Blaise Pascal and CNRS (France) and Jens Eriksson, Linköping University (Sweden)
14:00
Authors : Ruth Pearce 1, Anita Lloyd Spetz 2, Jens Eriksson 2 and Rositza Yakimova 2
Affiliations : 1) The National Physical Laboratory, U.K. 2) Linkoping University, Sweden

Resume : Graphene can be formed as a truly one dimensional material comprising a single atomic layer, however, it most often is produced along with some bi-layer or thicker areas of graphene. The effect of increasing layer number on the electronic properties of graphene has been the topic of much investigation but, as yet, the effect of layer thickness on the sensitivity of graphene gas sensors is little-studied. The effect of electron withdrawing and donating gases on the work function, carrier concentration and mobility of single and bi-layer graphene is discussed along with atomic force microscopy characterisation techniques which reveal the nanoscale functionality of a sensor surface. Single layer graphene has every atom on the surface, leading to electronic properties which are highly susceptible to doping from both the substrate and the environment. The linear band structure of graphene has a vanishing density of states at the Dirac point, with narrow bands above and below. If the Fermi level lies in this linear region, even a small change in carrier concentration leads to a large change in conductivity. Consequently, the conductivity of graphene can be dramatically altered by small concentrations of electron-withdrawing or donating gases. In contrast to single-layer graphene, the band structure of non-rotated bi-layer graphene is parabolic, with a broader density of states near the Dirac point, arguably making it a less sensitive sensor material. Atomic force microscopy (AFM) is a well-known technique for mapping nanoscale changes in the topography of sensor materials. Many other modes of operation can also be used to give information about the mechanism of response of a sensor device. For example, scanning Kelvin probe microscopy gives information about the uniformity of the work function of a surface. In graphene this enables the identification of areas of graphene of different thicknesses. Environmental scanning Kelvin probe microscopy, where the work function of the surface is mapped in controlled environments, is a useful tool for visualisation of the relative changes in work function over sensor devices. The effect of changing environment on each component of the device can be measured giving insight into the mechanism of sensor response at the nanoscale. Examples of such effects include a change in voltage drop between the contacts and the sensor material, and different changes in work function for areas of the sample where there are surface additives or varying thicknesses of sensor material. Additional AFM operating modes, such as force curve mapping, can be used to map the adhesion of a sensor material giving information regarding how strongly a molecule sticks to the sensor surface. For example, hydrophilic and hydrophobic tip coatings provide maps of how strongly polar molecules are attracted or repelled from the sensor surface. The relative changes in work function of a graphene sample containing single and bi-layer graphene has been mapped using environmental scanning Kelvin probe microscopy. The work function of graphene is shown to be sensitive to many atmospheric components such as O2 and water vapour and pollutants such as NO2, showing the largest response to stronger electron donating or withdrawing molecules. We demonstrate increasing sensitivity to changing environmental conditions with decreasing graphene layer thickness. A significantly larger change in the work function was observed for single layer graphene in the presence of electron donating (NH3) and withdrawing (NO2) gases than for bi-layer graphene [1]. Moreover, resistance measurements show that a single layer graphene gas sensor demonstrates a larger change in resistance than a multi-layer (MLG) graphene sensor on exposure to NO2 [2][3]. We calculate that the measured gating sensitivity difference between single layer graphene and bi-layer graphene is not fully accounted for by the difference in density of states, which is linear for single layer graphene and parabolic for bi-layer graphene. The adsorption of water vapour was observed to change the work function of single layer graphene dramatically, whereas the work function of bi-layer changed to a lesser extent over a wide range of relative humidity. We use force curve mapping to show the change in adhesion of graphene domains of different thicknesses and demonstrate that hydrophobicity increases with epitaxial graphene layer thickness. These results indicate the preferential adsorption of water vapour on single layer graphene compared to bilayer graphene. Surface contamination was also observed to preferentially deposit on either single or bi-layer graphene, which may also alter the adhesion relative properties of the graphene thicknesses. Knowledge of the affinity of environmental adsorbates to graphene and the effect they have on the electronic properties of graphene is necessary for producing environmentally stable devices as well as accurate and precisely calibrated environmental sensors. We demonstrate that a combination of effects leads to the increasing environmental sensitivity of graphene with reducing layer number. This work has implications for gas sensor research and suggests that a well-controlled and homogeneous single layer of graphene is essential in order to optimise sensitivity and uniformity of device response. AFM techniques are demonstrated to be a very useful tool in the characterisation of sensor material and devices, revealing the areas of the device most responsible for the sensor response. 1. Pearce, R.; Eriksson:, J.; Iakimov, T.; Hultman, L.; Spetz, A. L.; Yakimova, R., On the differing sensitivity to chemical gating of single and double layer epitaxial graphene explored using Scanning Kelvin Probe Microscopy. ACS Nano 2013, 7 (5) 4647- 4656 2. Pearce, R.; Iakimov, T.; Andersson, M.; Hultman, L.; Spetz, A. L.; Yakimova, R., Epitaxially grown graphene based gas sensors for ultra sensitive NO2 detection. Sensors and Actuators B: Chemical 2011, 155 (2), 451-455 3. Pearce, R.; Yakimova; Eriksson, J.; Hultman, L.; Andersson, M.; Lloyd Spetz, A., Development of FETs and Resistive Devices Based on Epitaxially Grown Single Layer Graphene on SiC for Highly Sensitive Gas Detection. Materials Science Forum, Silicon Carbide and Related Materials 2011, (717 - 720), 687-690

B.B.III.1
15:00
Authors : A. Martucci (1), M. Cittadini (1), M. Bersani (1), F. Perrozzi (2), L. Ottaviano (2), W. Wlodarski (3)
Affiliations : (1) Università di Padova, Dipartimento di Ingegneria Industriale, Italy; (2) Università dell'Aquila, Dipartimento di Scienze Fisiche e Chimiche, Italy; (3) RMIT University Melbourne, School of Electrical and Computer Engineering, Australia

Resume : Partially reduced graphene oxide (GO) coupled with Au or Ag nanoparticles (NPs) have been used for optical gas sensing with the aim of combining the semiconducting and photocatalytic activity behavior of the GO and the Localized Surface Plasmon Resonance (LSPR) of the noble metal NPs. The synergistic interplay between these materials resulted in an enhancement of the photocatalytic properties of GO, extending them to the visible range where the LSPR of metal NPs can be used as an optical probe. The sensor has been prepared by depositing partially reduced GO flakes over a monolayer of gold or silver NPs, chemically attached to a functionalized fused silica substrate. We observed a blue-shift of the LSPR peak due to the injection of electrons into the metal NPs as a consequence of the interaction of the GO with the reducing gases (H2), mediated by the adsorbed oxygen on GO. On the other hand, the interaction with NO2 (which is an oxidizing gas) induces a red-shift in the SPR peak of the metal NPs. The sample with Au NPs showed the best sensing performances and it was also demonstrated that the coupling of Au or Ag NPs with GO can provide a wavelength-dependent sensing response for different gas, allowing the realization of a selective sensor. While the use of GO for gas sensing has been covered in multiple reports, with the GO-Au NPs system already employed as a resistive gas sensor, only very recently GO has been used in an optical fiber array for the detection of vapors and

B.B.III.4
15:15
Authors : G. Reza Yazdi1, F. Akhtar1, T. Iakimov1,3, I. Ivanov1, A. Zakharov2, R. Yakimova1,3
Affiliations : 1-Dep of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping, Sweden 2-Maxlab, Lund University, S-22100 Lund, Sweden 3-Graphensic AB, Linkoping, Sweden

Resume : Graphene growth on Si face of SiC substrates was carried out in an inductively heated furnace at a temperature of 2000°C and at an ambient argon pressure of 1 atm. Graphene surface morphology, thickness, structure and electronic properties have been assessed by using AFM, LEEM, Raman, STM, STS, and EFM respectively. Sensitivity of epitaxial graphene on SiC to adsorption in open atmosphere is investigated. The surface morphology of the graphene layer shows a clean graphene surface after 1 month and completely decorated with adsorbed material after about 10 months. The aim of this work is to understand the reason of graphene surface modification. The adsorption on the surface which appears as bright spots is not uniform, the spots occur just on monolayer (ML) of graphene and not on 2ML. The second monolayer was distinguished by phase contrast mode and EFM and it is confirmed by the LEEM images as well. The EFM image of the large-scale area taken with Vtip=3V demonstrates two major levels of contrast, where the dark contrast corresponds to a single layer of graphene and the bright one to bilayer graphene On 2ML adsorption occurs on the edge of steps and wrinkles due to the geometry of the π bonds. The mechanism of this effect and dependency of their density on surface morphology will be elucidated. Strain differences between one and two monolayer graphene have been studied by Raman spectroscopy. Line Raman scanning clearly shows compressive strain in 2ML. Mapping is performed to obtain more precise results. The absence of adsorbed material on the second layer may be due to the present of compressive strain. It has been shown that the tensile strain on graphene layer makes the π bonds more active, which means in our case the compressive strain works in reverse way. To clean the graphene surfaces we have performed a series of annealing at different temperatures to find out the optimal regimes. The complete study will help to develop proper conditions for graphene maintenance before subsequent device process.

B.B.III.5
16:00
Authors : R.Yatskiv, J. Grym, M.Verde, M. Hamplova, P. Gladkov
Affiliations : Institute of Photonics and Electronics, Academy of Sciences CR, v.v.i.

Resume : Over the past decade ZnO nanostructures of various shapes have been intensively investigated. These nanostructures are ideal for studying transport mechanisms in low-dimensional systems, which represent a great promise for the development of a new generation of nanodevices with high performance. A low temperature chemical method developed by L. Vayssieres(L.Vayssieres 2003 Adv. Mater.15 464-466) was used to grow ZnO nanorods (NRs). Vertical arrays of hexagonal ZnO NRs with dimensions given by the reaction time were grown in aqueous solutions of zinc nitrate and hexamethylenetetramine at 95°C on partly photoresist-masked Si and ZnO substrates. The quality of as-grown ZnO NR was checked by photoluminescence spectroscopy at different temperatures from 4 to 300 K. A layer of ZnO NRs was used for the fabrication of Schottky diodes (SDs). A Schottky contact with a diameter of about 1 mm was created by printing colloidal graphite on top of the ZnO NRs. The photoresist was removed to create a Ga-In ohmic contact on a bare substrate. SDs were characterized by the measurement of current voltage (I-V) characteristics. The values of the barrier height and of the ideality factor extracted from I-V characteristics were 0.70 eV and 3.46, respectively. Deterioration of the quality of graphite/ZnO NRs SD as compared with the graphite/ZnO SD (R. Yatskiv and J. Grym 2012 Appl.Phys. Lett. 101 162106) can be explained by the increased density of structural defects of the ZnO NRs.

B.B.PI.3
16:00
Authors : Abhishek KUMAR(1,2), Jérôme BRUNET(1,2), Amadou NDIAYE(1,2), Alain PAULY(1,2), Michele PENZA(3), Christelle VARENNE(1,2), Marco ALVISI(3)
Affiliations : 1. Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand, France 2. CNRS, UMR 6602, Institut Pascal, F-63171 Aubière, France 3. ENEA, Brindisi Technical Unit of Technologies for Materials, PO Box 51-Br4, I-72100 Brindisi, Italy

Resume : Phthalocyanines are molecular semiconducting materials whose optical, electrical and chemical properties lead to many applications like dyeing, catalysis, molecular electronic or gas sensor development. Their physical and chemical properties can be modified by the grafting of the functional groups at their peripheral position or the substitution of the central atom. Thus, these materials can be adapted to different applications. This is especially attractive for chemosensors: such a sensitive material can be tailored to the pollutant to be detected and its processability can be optimized. Tetra-tert-butyl metallophthalocyanines (ttb-MPc) appear as suitable sensing materials for gas sensors aimed to aromatic hydrocarbons detection. On one hand, benzene rings of phthalocyanine macrocycle are good adsorption sites for aromatic analytes through pi-pi stacking interactions. On the other hand, peripheral butyl groups enhance the solubility of phthalocyanines into solvents, increasing the number of possible thin film deposition modes. This work reports the elaboration and the characterization of ttb-CuPc and ttb-ZnPc QCM-based sensors for the detection of benzene, toluene and xylene. Measurements are realized at room temperature, frequency drifts of QCM transducers due to temperature variations being corrected. Sensor sensitivity, stability, reproducibility, resolution and threshold have been determined. The insensitivity towards CO, H2S, NO2 and ethanol was also established.

B.B.PI.8
16:00
Authors : R. Calavia, S. Roso, R. Vázquez, I. M. Szilagyi* and E. Llobet
Affiliations : MINOS-EMaS, Universitat Rovira i Virgili, Tarragona, Spain *Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, Hungary

Resume : Here we discuss atomic layer deposition (ALD) to conformably coat porous anodic alumina (PAA) templates with thin films of zinc oxide (thickness up to 15 nm) in view of producing nanostructured gas sensors. The gas sensing properties of nanostructured metal oxide films, sputter-deposited on PAA templates had been studied by our group [1,2]. For such films to continuously cover the pores of PAA, a step of pore widening is unavoidable, which significantly reduces the length to width aspect ratio of pores and, therefore, surface area. In contrast, ALD allows for avoiding the pore widening step needed with sputtering and this results in nanostructured metal oxides with increased surface area. The PAA templates were obtained by the anodising of an Al/Ti bilayer in tartaric acid at a constant current density of 4.5 mA/cm2 (pore width and length were 50 and 700 nm and interpore distance was 180 nm). ALD was run at 100ºC. Diethyl zinc and water were used as precursors and 30-60-90 cycles with 0.3 s pulse and 15 s purge were performed for getting 5, 10 and 15 nm thick, amorphous ZnO films. SEM images of FIB cross sectional cuts show that a conformal coating of PAA is obtained. After an annealing step, the gas sensing properties of these films to ethanol, nitrogen dioxide both in dry and humid air were studied. Results are promising and show enhanced sensitivity at moderate operating temperatures (250ºC). [1] Int. J. Hyd. Energy, 38 (2013) 8011-8021 [2] Anal. Chem., 84 (2012) 7502-75

B.B.PI.10
16:00
Authors : Amadou NDIAYE1,2, Michele Penza3, Jérôme BRUNET1,2, Marco Alvisi3, Alain PAULY1,2, Christelle VARENNE1,2
Affiliations : 1Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand, France 2 CNRS, UMR 6602, Institut Pascal, F-63171 Aubière, France 3 ENEA Technical Unit of Technologies for Materials, Brindisi Research Center, I-72100 Brindisi, Italy,

Resume : Carbon nanotubes (CNTs) present peculiar transport properties which are sensitive to surface reaction (gas adsorption). As a consequence CNTs are a judicious choice for the development of efficient gas sensors [1]. Sensing material we are developing in our study use the main advantage of CNTs i.e. their high surface area, an important property to reach higher sensitivities [2]. In terms of sensing, functionalization (non-covalent) is a good way to process the CNTs and bring additional functionalities for gas detection. Our sensing materials consist of CNTs hybrid materials obtained upon functionalization with macrocycles like porphyrins or phthalocyanines to achieve VOCs (Volatile Organic Compounds) detection like Benzene, Toluene and Xylenes. To understand the gas/material interaction between VOCs and CNTs hybrid materials, we have performed two studies: first, we have simultaneously investigated QCM and SAW transduction modes, and second, we have proceeded to gas sensing experiment towards interfering gases (NO2, H2S, and Ethanol etc). The sensing materials were prepared and characterized by standard techniques (UV-Vis spectroscopy, TGA, TEM, Raman analysis). The results have provided information on the ability of these CNTs-based hybrid materials to detect VOCs while they seem to be insensitive towards other interfering gases, at room temperature. References: [1] S. Liu et.al. Coord. Chem. Rev. 254 (2010) 1101. [2] A.L. Ndiaye et.al. Sens. Actuators B 162 (2012) 95.

B.B.PI.11
16:00
Authors : S. Roso, F. Guell*, E. Llobet
Affiliations : MINOS-EMaS, Universitat Rovira i Virgili, Tarragona, Spain *Departament d'Electronica, Universitat de Barcelona, Barcelona, Spain

Resume : Zinc oxide (ZnO) is an interesting material with optoelectronic and gas-sensitive properties. Here we have synthesized ZnO nanowires (NWs) via the vapor-liquid-solid technique. This is a catalyst assisted chemical vapor deposition suitable for obtaining good quality NWs. We have chosen sapphire substrates with different crystallographic orientations, namely, c-plane, r-plane and a-plane. Au clusters were previously deposited on the substrates by sputtering and annealing. Then, 40 nm wide and 1 micro long nanowires were grown at 900?C in a horizontal quartz furnace, using ZnO powder and graphite as precursors and Ar as carrier gas. NWs grew oriented in different directions or with different morphologies depending on the crystalline planes of the substrates. For example NWs grew at 51? and 129? (on c-plane substrates), vertically aligned (on a-plane) or showing a nanorod structure (on r-plane). The response of ZnO NWs to different gases and concentrations was tested at different working temperatures. The optimum operating conditions have been identified and the dependency of the gas response on the orientation of NWs has been studied (higher gas response is observed for r-plane and a-plane samples). Full details on growth mechanisms, morphology, crystalline phase and gas response to CO, C6H6 and EtOH will be given. Enhanced response can be due to the lower amount of NW to NW contacts and higher specific surface found in samples that grow vertically aligned.

B.B.PI.13
16:00
Authors : Zeggai Oussama , Ould-Abbes Ammaria , Zeggai Hichem
Affiliations : Research unit of Materials and Renewable energies (URMER), University Abou Bakr Belkaïd, B.P. 119, Tlemcen, Algeria

Resume : Semiconductor nanowires are nano-objects to a very promising dimension for the realization of future high-performance electronic components. The development of semiconductor nanowires (ZnO) has been a great interest in the scientific community over the past ten years. These one-dimensional objects have been developed using various techniques such as molecular beam epitaxy or vapor phase epitaxy. The ZnO is one of the attractive semiconductor due to their excellent electrical and optical properties (large exciton binding energy, very large gaps to the emission and detection of light in the UV, for surface functionalization the realization of biological sensors, etc. ....). The possibility to study recently nano-objects ZnO resulted in a large number of scientific works in the field of biology and health. In this work we demonstrate the role of electrical and electrochemical properties of nanowires (ZnO), and the contact with the biological catalysts such as enzymes in biological solutions for the detection of analytes (glucose, CO2 ....).

B.B.PI.15
16:00
Authors : I. Veselova, N. Borzenkova, O. Vashkinskaya, T. Shekhovtsova, A. Sidorov, A. Grigoryeva, E. Goodilin
Affiliations : Lomonosov Moscow State University, Moscow, Russia

Resume : The creation of sensitive and selective sensor systems for the determination of different biologically active compounds (phenols, flavonoids, catecholamines, phenothiazines, dibenzothiophene and its oxidation products, and organic peroxides) without preliminary pretreatment of samples with complex matrices is the promising direction of modern biochemical analysis. The determination of such compounds is necessary to control the quality of pharmaceutical and food products, plant materials, diesel oil, environmental samples and etc. In the present work the solid-phase biosensors with photometric, fluorescent and SERS detection of an analytical signal were developed. The action of the proposed photometric, fluorescent biosensors is based on the molecular recognition of the above mentioned analytes by horseradish peroxidase included into a self-assembled optically transparent film or hydrogel of a biopolymer (chitosan). The main peculiarity of the proposed biosensors is the measurement of the analytical signal as an absorbance or emission of a glass slide with biorecognizing films {polyelectrolyte-enzyme-photometric or fluorescent reagent}. The solid-phase photometric and fluorescent indicator systems for each group of the above mentioned analytes (twelve systems totally) were elaborated. The novel approach for detection of SERS “invisible” molecules (such as dibenzothiophene and its oxidation products) based on formation of charge–transfer complexes with different substituted benzoquinones immobilized in chitosan films was developed. This investigation was financially supported by RFBR (Projects 12-03-00249-а, 13-03-00441-a, 14-03-01151-a).

B.B.PI.16
16:00
Authors : Oral Ualibek, Ruggero Verre, Ehsan Razvani, Brendan Bulfin, Karsten Fleischer, Igor V. Shvets
Affiliations : Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), School of Physics, Trinity College Dublin, Dublin 2 , Ireland; Department of Applied Physics, Chalmers University of Technology, Goteborg, Sweden; Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), School of Chemistry, Trinity College Dublin, Dublin 2 , Ireland; School of Physics, Trinity College Dublin, Dublin 2 , Ireland

Resume : Highly ordered self-assembled plasmonic nanoparticle (NP) arrays have been produced by glancing angle deposition (GLAD) on faceted c-plane Al2O3 templates. This procedure allows for engineering and tuning of their optical and geometrical properties via control of growth parameters. The NP shape can be tuned by changing the substrate temperature during deposition. The structures showed a strong optical anisotropy in the visible region, with a shift between longitudinal and transverse resonances. This phenomenon has been attributed to the combined effects of both shape anisotropy and strong inter-particle interaction. Due to the presence of “hot spot” areas in the inter-particle sites, the structure is appealing for surface enhanced Raman spectroscopy measurements and biosensing applications. The average NP diameter and inter-particle distance are below the limitations of lithographic methods, with standard deviations of ~20%. We could tune the plasmonic resonance peak within the range of 1.1 eV to 2.6 eV by changing the material of the nanoparticles, their size and shape. Thus, engineering of the optical properties of the array is readily achievable by the versatile GLAD method. With regard to the application potential of the GLAD technique, we present SERS results in which the Raman signal achieves an enhancement factor of 10^7 due to the presence of the underlying NP arrays.

B.B.PI.18
16:00
Authors : M.C. Sportelli1, D. Hoetger2, R.A. Picca1, K. Manoli1, C. Kranz2, B. Mizaikoff2, L. Torsi1, N. Cioffi1
Affiliations : 1 Chemistry Department, Univ. degli Studi Bari Aldo Moro, Italy 2 Institute of Anal. and Bioanal. Chemistry, University of Ulm, Germany

Resume : ZnO is one of the most important functional oxides. The electrochemical synthesis of ZnO is particularly interesting as green, cheap and easy procedure1. Application of ZnO to fabricate gas sensors is widespread: the key-issues hereby is the development of smart ZnONPs with tailored properties for solid-state sensors2. Here we report on the galvanostatic aqueous electrosynthesis of ZnONPs3 in the presence of sodium polystyrensulfonate, often used as stabilizer for NPs in sensing applications4. Calcination of colloids was carried out at 300/600°C. All nanomaterials were characterized by TEM, UV-Vis, IR and XPS. Detailed investigation of photoelectronic and Auger XPS spectra was accomplished. We prepared high-performance OFETs, by preparing a poly-3hexyltiophene (P3HT)-ZnO multilayered composite with improved electronic figures of merit in respect to bare P3HT devices5; preliminary successful experiments on the use of ZnONPs in biosensors devices were carried out. 1. M.C. Sportelli, et al., Recent trends in the electrochemical synthesis of ZnO nanocolloids, in CRC Concise Encyclopedia of Nanotech., submitted. 2. B.Bhooloka Rao, Mat. Chem. Phys. 2000, 64, 62-65. 3. K.G. Chandrappa et al., Nano-Micro Lett. 2012, 4, 14-24. 4. L. Wan, et al., Coll. Surf. A 2012, 396, 46–50. 5. M. D. Angione, et al., PNAS 2012, 109, 6429–6434.

B.B.PI.19
16:00
Authors : Elena Dilonardo 1, Michele Penza 2, Marco Alvisi 2, Domenico Suriano 2, Gennaro Cassano 2, Francesco Palmisano 1, Luisa Torsi 1, Nicola Cioffi 1
Affiliations : 1 Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Campus Universitario, via Orabona 4, 70126 Bari, Italy 2 ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic DevelopmentTechnical Unit for Materials Technologies - Brindisi Research Center, PO Box 51 Br4; I-72100 Brindisi -Italy

Resume : A facile one-step strategy based on sacrificial anode electrolysis was developed to obtained stabilized gold nanoparticles (Au NPs) directly deposited on the surface of nanostructured ZnO and ZrO2 powders, previously synthesized by sol-gel method and subjected to thermal annealing prior to the electrosynthesis step. The resulting nanocomposite is proposed as active layer in resistive sensors for NO2 detection. The nanostructured composite materials were firstly thermally annealed under mild conditions and, subsequently, they were morphologically and chemically characterized using transmission and scanning electron microscopies, as well as X-ray photon electron spectroscopy which revealed the formation of nanoscale gold, and its successful decoration on metal oxide nanoparticles. Au functionalized metal oxide thin films were tested as active layers for NOx sensing application. Nitrogen dioxide sensors based on drop-casted Au-doped and un-doped metal oxide (MOX) thin films were prepared. The effect of the metal oxide composition and of the Au-doping on the sensor performance (e.g., gas response and baseline resistance drift) were analyzed. In particular, the gas sensing properties of MOx and hybrid nanostructured thin films were studied at various temperatures for a wide range of concentration for analyzed gas. Moreover, the response of these sensors towards some interfering species such as CO, NH3, CH4 and SO2 were also analyzed.

B.B.PI.21
16:00
Authors : Xu Yong, Hu Xue Feng, Wang Rui , Li Tao,Qin Wei Wei, Xu Meigui, and Wei Zhang*
Affiliations : State Key Laboratory of Material-oriented Chemical Engineering and School of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, PR China

Resume : The increased emission of carbon dioxide (CO2) and other greenhouse gases since the mid-20th century has been thought to be the cause of the increase in the average near-surface air and ocean temperature of the earth, a phenomenon known as global warming. Efforts are being undertaken to mitigate the greenhouse gas concentration by monitoring and subsequently reducing CO2 emission from the combustion of fuel in vehicles and the burning of coal in power plants. Therefore, it is important to develop low-cost, sensitive, resettable sensors that can be used to monitor the CO2 concentration in industrial exhaust gases. In this article, we report on a high-performance hydrided graphene and ZnO carbon dioxide (CO2) gas sensor fabricated by pulsed laser ablation and grapheme transfer technology. Unlike other solid-state gas sensors, the graphene sensor can be operated under ambient conditions and at room temperature. Changes in the device conductance are measured for various concentrations of CO2 gas adsorbed on the surface of grapheme and ZnO films. The conductance of the grapheme gas sensor increases linearly when the concentration of CO2 gas is increased from 10 to 100 ppm. The advantages of this sensor are high sensitivity, fast response time, short recovery time, and low power consumption. *Corresponding author, zhangw@njut.edu.cn

B.B.PI.33
16:00
Authors : Qin Wei Wei, Wang Rui, Gao Zhi Qiang, Li Tao, Hu Xue Feng,Xu Meigui, Huang Shengming, Liang Qi, and Wei Zhang,*
Affiliations : a State Key Laboratory of Material-oriented Chemical Engineering and School of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, PR China b School of Physical Science, Hefei University of Technology, Hefei, Anhui 230009, PR China

Resume : Recent discovery in ZnO nanogenarator has spurred tremendous interest in micro-sensor power application. The fundamental principle of ZnO nanogenarator is to utilize the environmental mechanical energy, which is available everywhere from irregular vibrations, light airflow, noise and human activity with a wide spectrum of frequencies and time-dependent amplitudes. The first prototyping of a nanogenarator by means of ZnO piezoelectric nanowire (NW) arrays have demonstrated to able to drive sensor network nods in micro-power range. ZnO piezoelectric thin films have also been successfully transferred onto flexible substrates for stretchable energy harvesting, which suggests new possible applications of piezoelectric nanomaterials. However so far the fundamental mechanism from thin film piezoelectric generator is still unclear. To further clarify the effect of stress-induced and nonsymetry charge center promoted electrical potential is critical for large power output from ZnO nanogenerator. power output from NW nanogenarator is still in the power range micro watt, which is still far way from milli-power output source requested by most applications of individual sensor and sensor network system. The lacking of high power output in current ZnO NW generator is partially attribute to non-well c-axis oriented crystalline of ZnO NW material and low yield in NW device[5], both are synthesized by chemical method. Therefore to explore new approach for ZnO NW material synthesis to enhance piezoelectric effect is desirable. In this paper, the effects of the stress on piezoelectric response for ZnO film grown by pulsed-laser deposited (PLD) are investigated. To promote differerent film stress, the ZnO films are deposited at different thcknessa and different temperature. Structurally, special emphasis is placed on XRD characterizations of the films. Additional characterizations using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) will be detailed at a later date. The piezo-electric properties of these films are characterized by Piezoelectric Force Microscopy (PFM). The observed corresponds of piezoelectric (PE) property to stress is also theoretically investigated. *Corresponding author, zhangw@njut.edu.cn

B.B.PI.35
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Integration of Nanosensors for Scale-Up : Eduard Llobet, University Rovira i Virgili (Spain) and Albert Romano-Rodriguez, Universitat de Barcelona (Spain)
08:45
Authors : Michele Penza and EuNetAir Consortium (www.cost.eunetair.it)
Affiliations : ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development Technical Unit for Materials Technologies - Brindisi Research Center, PO Box 51 Br4; I-72100 Brindisi, ITALY

Resume : This is a overview of the COST Action TD1105 EuNetAir - European Network on New Sensing Technologies for Air-Pollution Control and Environmental Sustainability - funded in the COST framework. The objective of the Concerted Action (2012-16) is to develop new sensing technologies for Air Quality Control at multidisciplinary scale by coordinated research on nanomaterials, sensor-systems, air-quality modelling and standardised methods to support environmental sustainability with special focus on SMEs. This international Networking, coordinated by ENEA (Italy), includes over 80 institutions and over 170 international experts from 28 COST Countries (Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Israel, Italy, Latvia, The Former Yugoslav Republic of Macedonia, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom) and 7 Non-COST Countries (Australia, Canada, China, Morocco, Russia, Ukraine, USA) to create a S&T critical mass in the environmental issues. This COST Action focuses on a new detection paradigm based on sensing technologies at low cost for Air Quality Control and set up an interdisciplinary top-level network to define innovative approaches in sensor nanomaterials, gas sensors, devices, wireless sensor-systems, distributed computing, methods, models, standards and protocols for environmental sustainability within the European Research Area.

B.B.IV.1
09:00
Authors : Martin W. G. Hoffmann (1,2,3), Olga Casals (1), Francisco Hernandez-Ramirez (1,3), Andreas Waag (2), Hao Shen (2), J. Daniel Prades (1)
Affiliations : 1) Department of Electronics, University of Barcelona, Barcelona, Spain 2) Institut f?r Halbleitertechnik, Technische Universit?t Braunschweig, Braunschweig, Germany 3) Department of Advanced Materials for Energy Applications, Catalonia Institute for Energy Research (IREC), Barcelona, Spain

Resume : Low power consumption and high specificity are two of the most sought after requirements for future gas sensors technologies. In this contribution, new device concepts capable to detect gases without the need of external power sources to activate the sensor-gas interaction or to generate a read out signal will be described [1]. It will be demonstrated that sensors featuring zero power consumption can be achieved by integrating the sensing components and the energy sources intimately, at the nanoscale. On the other hand, a rational methodology to design organic surface functionalizations that provide high selectivity towards single gas species will also be discussed [2]. Specifically, theoretical results, confirmed experimentally, indicate that precisely tuning the sterical and electronic structure of the sensor material and the organic functionalization can lead to unprecedented selectivity values, comparable to those typical of bioselective processes. Finally, the first attempts to combine both strategies in one single, solid-state, cost-effective, integrated device will also be presented. [1] M. W. G. Hoffmann, A. E. Gad, J. D. Prades, F. Hernandez-Ramirez, R. Fiz, H. Shen, S. Mathur, Nano Energy 2013, 2, 514?522. [2] M. W. G. Hoffmann, J. D. Prades, L. Mayrhofer, F. Hernandez-Ramirez, T. T. J?rvi, M. Moseler, A. Waag, H. Shen, Adv. Funct. Mater. 2013, DOI: 10.1002/adfm.201301478

B.B.IV.2
09:30
Authors : A. Koeck, S. Defregger, E. Kraker, S. Steimnhauer, T. Maier, G.C. Mutinati, K. Rohracher, J. Siegert, F. Schrank, E. Wachmann
Affiliations : Materials Center Leoben, AIT Austrian Institute of Technology, ams AG

Resume : The employment of metal oxide nanowires is a very powerful strategy to push the performance of gas sensing devices. Nanowires have a high surface to volume ratio and a strong interaction with the surrounding gas. Nanowire based sensors thus provide very sensitive gas detection and have the advantage of improved stability due to high crystallinity. However, efficient and reliable nanowire integration with standard CMOS technology remains a major challenge. We present gas sensor devices employing metal oxide nanowires integrated on micro hotplates devices, which are fabricated in standard 0.35µm CMOS technology combined with a MEMS etching process. Three different nanowire materials are employed for realization of the gas sensor devices: SnO2, CuO, and ZnO. The specific processes developed for the CuO and ZnO nanowires enable their direct synthesis on the CMOS micro hotplates; the SnO2 nanowires, however, require a transfer process from a specific synthesis wafer to the CMOS micro hotplates. The presented technologies can be used in a CMOS backend process and enable the fabrication of fully silicon integrated SnO2, CuO and ZnO nanowire gas sensing devices. The gas sensing performance of the nanowire based gas sensor devices to a variety of gases (CO, CO2, VOCs, H2, H2S) relevant for environmental monitoring will be presented. The approach towards a fully CMOS integrated multi-parameter gas sensing device will be discussed.

B.B.IV.3
11:00
Authors : Elena Dilonardo 1, Michele Penza 2, Marco Alvisi 2, Domenico Suriano 2, Riccardo Rossi 2, Francesco Palmisano 1, Luisa Torsi 1, Nicola Cioffi 1
Affiliations : 1 Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Campus Universitario, via Orabona 4, 70126 Bari, Italy. 2 ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development Technical Unit for Materials Technologies - Brindisi Research Center, PO Box 51 Br4; I-72100 Brindisi – Italy.

Resume : In the present study, Au-surfactant core-shell colloidal nanoparticles (Au NPs) with controlled dimension and composition were synthesized by sacrificial anode electrolysis. Transmission electron microscopy revealed that Au NPs core diameter is comprised between 8-12 nm, as a function of the electrosynthesis conditions; UV-vis spectroscopy showed that size effects affect position and width of the surface plasmon resonance peak. Moreover, surface spectroscopic characterization by XPS analysis confirmed the presence of nanosized gold phase. Controlled amounts of Au NPs were then deposited electrophoretically on CNTs networked films. The resulting hybrid materials were morphologically and chemically characterized using TEM, SEM and XPS analyses, which revealed the presence of nanoscale gold, and its successful deposition/decoration on CNTs. Au NPs/CNTs networked films were tested as active layers in a two-pole resistive NO2 sensor for sub-ppm detection. Au-NPs/CNTs exhibited a p-type response with a decrease in electrical resistance upon exposure to oxidizing NO2 gas and an increase in resistance upon exposure to reducing gases (e.g., CO, SO2). It was also demonstrated that the sensitivity of Au NP/CNTs-based sensors depends on Au-loading; therefore the impact of Au loading on gas sensing performance was investigated as a function of the working temperature, gas concentration and interfering gases.

B.B.V.2
11:45
Authors : S. Baldo, V. Scuderi, L. Tripodi, A. La Magna, S. G. Leonardi, N. Donato, G. Neri, L. Romano, S. Scalese
Affiliations : Istituto per la Microelettronica e Microsistemi, CNR, Catania, VIII Strada 5, 95121 Catania (Italy); Dipartimento di Ingegneria Elettronica, Chimica e Ingegneria Industriale, Università di Messina, Contrada di Dio, Salita Sperone 31, Messina (Italy); Dipartimento di Fisica ed Astronomia, Università di Catania, via S. Sofia, 95125 Catania (Italy);

Resume : In this work we report about the development of CNTFET back-gated transducers, with Carbon Nanotubes (CNT) layers playing the role of the channel, and their electrical characterization for sensing applications. The CNTs deposition was performed by electrophoresis on an interdigitated electrode region created on a SiO2/Si substrate. Different kinds of CNTs have been used (MWCNTs by arc discharge in liquid nitrogen, MWCNTs by CVD and SWCNTs) and the electrical characterization of the devices was performed in NH3 and NO2 controlled environment. Preliminary data have shown an increasing of the channel resistance after addition of NH3, whereas during the exposure to NO2 a decrease in the channel resistance was noted. Anyway, different kinds of CNTs show different sensitivities to the two gas environments. Furthermore, the formation of defects by ion implantation on CNTs was investigated by high resolution TEM. Raman analysis showed an increase of ID/IG ratio related to an increase of structural disorder, as expected. The observed behaviour of the devices can be explained in terms of the interaction between structural or chemical defects in CNTs and the gas molecules.

B.B.V.5
12:00
Authors : Jérôme BRUNET (1,2), Alain PAULY(1,2), Amadou NDIAYE(1,2), Christelle VARENNE(1,2), Abhishek KUMAR(1,2),Marc DUBOIS(3,4)
Affiliations : 1. Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand, France; 2. CNRS, UMR 6602, Institut Pascal, F-63171 Aubière, France; 3. Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France; 4. CNRS, UMR 6002, Institut de Chimie de Clermont-Ferrand, F-63177 Aubière, France.

Resume : The exponential development of nanomaterials opened the way to a new generation of devices with enhanced performances and new application fields. Among these new materials, nanocarbons are extensively investigated for the elaboration of electronic components like transistors, LEDs, electron sources and gas sensors. Since nanocarbonaceous materials offers high affinity with gases as exploited into sensing devices, we propose as complementary approach to shape nanocarbons as chemical filter for air cleaning. A large panel of pristine nanocarbons has been firstly studied: single and multi-wall nanotubes, nanowires, nanodiscs, activated carbons. Their filtering power, the interaction mechanisms involved with the target gases (O3, NO2, CO) as well as the physical and chemical properties of nanocarbons responsible for their filtering ability have been determined both from gas exposures and characterizations (EPR, Raman spectroscopy, NEXAFS). The relevance of original indigo/nanocarbons hybrid materials as O3 filter has been established too. The non-covalent functionalization of nanocarbonaceous materials by two wet chemical routes has been monitored by SEM, XRD and TGA. Performances like filtering efficiency, selectivity and sustainability have been especially assessed. As an application, we will discuss on the successful development of selective NO2 sensor-systems associating such a filter to phthalocyanine-based chemoresistor for the NO2 monitoring in ppb-range in air.

B.B.V.6
 
Modeling of Sensors and Sensor/Gas Interaction : Anita Lloyd Spetz Linköping University (Sweden) and University of Oulu (Finland) and Juan Ramon Morante, IREC and Universitat de Barcelona (Spain)
14:00
Authors : N. Abdelmalek, F. Djeffal, T. Bentrcia and M. Meguellati
Affiliations : LEA, Department of Electronics, University of Batna, Batna 05000, Algeria. E-mail: faycal.djeffal@univ-batna.dz, faycaldzdz@hotmail.com, Tel/Fax: 0021333805494

Resume : The Gate All Around GAA MOSFETs have emerged as excellent devices to provide the electrostatic integrity needed to scale down transistors to minimal channel lengths, and allowing a continuous progress in digital and analog applications. Employing this design for chemical and environment monitoring applications becomes more beneficial if the device is made in vertical cylindrical recrystallized silicon due to highly flexible process integration options. In this paper, a numerical investigation of a new pH-ISFET design, called the Junctionless Gate All Around Ion-sensitive field-effect transistor with oxide kernel (pH-JGAAISFET), is proposed, investigated and expected to improve the fabrication process and the sensitivity behavior for pH-ISFET sensor-based applications. The numerical investigation has been used to propose a new sensitivity performance and predict the device behavior. The comparison of device architectures shows that the proposed sensor exhibits a superior performance with respect to the conventional ISFET in term of electrical performances. The obtained results make the proposed sensor a promising candidate for low cost monitoring and high performance pH sensing applications.

B.B.VI.1
14:30
Authors : Massimiliano D'Arienzo, Lidia Armelao, Claudio Maria Mari, Riccardo Ruffo, Roberto Scotti, Franca Morazzoni
Affiliations : University of Milano Bicocca

Resume : The unique properties of SnO2 and WO3 nanocrystals which expose specific surfaces as chemical sensors have been recently reported. However, a clear assessment of the relative involvement of the crystal faces in the sensing mechanism is still under debate. To clarify this issue, we have carefully investigated the sensing behavior of SnO2 shape controlled nanoparticles in connection to the generation and the reactivity of their oxygen defects (VO•), detected by ESR, associating their abundance and reactivity to the exposed crystal faces and to the electrical response of the nanocrystals. Results indicate that the presence of the {221} and {111} surfaces enhances the generation of the VO• centers and boosts the sensing performance toward CO. A similar investigation was carried out on WO3 nanocrystals with tailored morphology and definite prominent surfaces. Their sensing performances toward NH3 were evaluated and, in order to deepen the role of the surfaces in the sensing mechanism, a comprehensive XPS investigation on the surface nitrogen species was also performed. It turned out that {020} and {002} high-energy surfaces represent privileged reactive sites for the NH3 oxidation and therefore are essential for enhancing the sensing properties. These outcomes may help to a more effective evaluation of the involvement of the crystal surfaces in the sensing mechanism and may shed some light on how crystal facet engineering can be better applied to design more efficient gas sensors.

B.B.VI.3
16:30
Authors : T M?rian1,2, N.Redon1,2, Z. Zujovic3, D. Stanisavljev4, JL Wojkiewicz1,2, M. Gizdavic-Nikolaidis3,4
Affiliations : 1 Univ Lille Nord de France, F59000 Lille, France 2Mines-Douai, CE, F-59508 Douai, France 3School of Chemical Sciences, the University of Auckland, Private Bag 92019, Auckland 1142, New Zealand 4 Faculty of Physical Chemistry, Studentski trg 12-16, 11001 Belgrade, University of Belgrade, Serbia

Resume : Ammonia and amines can originate from both various human initiated sources including animal husbandry, industry and combustion, composting operation, automobiles, cooking, tobacco smoke, and natural sources as biomass burning, and biodegradation of organic matter that contain proteins or amino acids. The adverse health effects of amines and ammonia are demonstrated and it is important to detect them for health and environment protection. Due to base properties of ammonia and amines, conducting polyaniline (PANI) can be used to create inexpensive gas sensors with a very low quantification limit and relatively short response time. The principle of measurement is based on the electrical variation of the resistance of an active layer submitted to the gas. Following this principle, we developed a new low cost organic electronic sensor with PANI composites to detect ammonia and trimethylamine at room temperature. Two types of nanocomposite materials were synthesized and optimized for gas detection at ppb levels. First a PANI doped with a sulfonic acid/ polyurethane composite was studied for ammonia detection. It was demonstrated that the percolation phenomena and the rate of doping can be used to enhance the response of the sensors at ppb levels. Second PANI nanofibers synthesized by microwave treatment were used for trimethylamine detection. It was shown that the use of percolation phenomena added to this particular nanostructure can make sensors with large response at ppb levels. In both cases, it is demonstrated that nanostructured conducting polymers are suitable for new generation of nanosensors for air quality control.

B.B.VII.2
17:00
Authors : Sebastian Pregl, Felix Zoergiebel, Lotta Roemhildt, Larysa Baraban, Walter M. Weber, Thomas Mikolajick, and Gianaurelio Cuniberti
Affiliations : Technische Universität Dresden, Faculty of Mechanical Science and Engineering, Institute for Materials Science, Materials Science and Nanotechnology Team, Hallwachsstrasse 3, 01069 Dresden, Germany

Resume : After the years of intense investigations, nanomaterials have entered the phase of commercial applications in medicine as drug carriers or labels contrast agents for magnetic resonance imaging, and convenient tool for biodetection. Prominent example is the use of nanoparticles in combination with fluorescent labels for large number of biochemical tests. During last decade a new class of biological sensors emerged, which relies on the use of nanomaterials i.e. nanoparticles or nanowires, for detection of biological molecules or of products of biologically catalyzed reactions. Within this novel group of the devices, silicon nanowire based field effect transistors represent a promising route for label-free detection of biochemical species. Here we present and fully characterize the biosensor platform based on NiSi2-Si-NiSi2 nanowire heterostructures. Such devices require integration of Schottky-barriers (SB) to provide the change in contact resistance, which can be further used for sensing. We focus on the following aspects of the biosensor functioning and characterization: (i) fabrication and characterization of the SB-FET nanodevices; (ii) biochemical functionalization of the silicon nanowire sensors using aptamers, also known as “artificial antibodies”; (iii) demonstrate sensing capabilities of the developed devices.

B.B.VII.4
18:00
Authors : M. Bouvet1, T. Sizun1, J.-M. Suisse1, T. Patois2, and B. Lakard2
Affiliations : 1: Institut de Chimie Moléculaire de l'Université de Bourgogne, Dijon, FRANCE 2: UTINAM, Besançon, FRANCE

Resume : Hybrid materials combining polypyrrole (PPy) with ionic macrocycles as counterions have been electrosynthesized at the surface of platinum interdigited electrodes. The obtained films revealed to be more homogeneous compared to PPy synthesized with small counterions, with a strongly smaller roughness. The films exhibited a higher sensitivity to ammonia (NH3), with a very good reversibility and with a stable response in a broad range of relative humidity (20-80 % RH). Overall, we present the advantages of combining ionic phthalocyanines (Pc) with PPy in enhancing the properties of the final material. Synergetic effects in the structure and properties of PPy-Pc materials open the way to their development in the field of hybrid material and their use for chemosensing. At a given RH value, the current baseline is very stable, the response to NH3 is highly reproducible, and proportional to the NH3 concentration. As a function of the RH, the relative response varies differently depending on the NH3 concentration. It increases, at 25 ppm, but increases then decreases at 45 and 90 ppm. However, at these NH3 levels, discrimination still occurs between the different concentrations. This result is very important, since it means that, whatever the RH in the range 20-80%, the device is capable to discriminate between these different NH3 concentrations.

B.B.VII.8
Start atSubject View AllNum.Add
09:15
Authors : Amer Al-Nafiey, Palaniappan Subramanian, Ahmed Addad, Sabine Szunerits, Brigitte Sieber, Rabah Boukherroub
Affiliations : Institut de Recherche Interdisciplinaire (IRI, USR CNRS 3078), Université Lille 1;Unité des Matériaux Et Transformations (UMET, UMR 8207), Université Lille1

Resume : Abstract The reduction of graphene oxide (GO) has been a subject of intense efforts in the last decade. Many efforts have been devoted to the preparation of chemically modified GO and graphene composites aiming at a better processability of graphene and modulating at wish its electronic, optical properties and electrochemical properties.1 Functionalization of graphene enables indeed this material to be processed by solvent-assisted techniques and prevents its agglomeration and thus maintaining the inherent properties of graphene crucially important for their end application. Reduced graphene oxide (rGO) is prepared through the reduction of GO using different means. The technique consists of the initial oxidation of graphite to graphite oxide, followed by the subsequent mechanical/chemical or thermal exfoliation of graphite oxide to graphene oxide (GO) sheets, and their reduction to graphene.2 Various approaches have been investigated for the reduction or reduction/functionalization of GO using chemical, electrochemical, thermal or photochemical means.2 Hydrazine monohydrate is still the most widely used reductant, mainly due to its strong reduction activity to eliminate most oxygen-containing functional groups of GO and its ability to yield stable rGO aqueous dispersions. However, with hydrazine as the reducing agent, its residual trace may strongly decrease the performance of rGO-based devices. In addition, hydrazine is a highly toxic and potentially explosive chemical. To avoid using hydrazine, many environmentally friendly and high-efficient reductants have been developed and used for the reduction of GO, including vitamin C, amino acids, reducing sugars, alcohols, hydroiodic acid, reducing metal powder, sodium citrate, tea, lysozyme, dopamine, etc.3 Herein, we report on simultaneous reduction/functionalization of graphene oxide (GO) using environmentally friendly reagent, arginine (Arg). This one-step reaction consists of a simple reaction of GO with Arg at 100°C for 4 h. Furthermore, this approach was successfully applied for the synthesis of rGO decorated with metal nanoparticles. The resulting materials have been characterized using UV-vis spectrometry, FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical measurements. Finally, the catalytic activity of rGO/metal nanoparticles has been evaluated for the reduction of nitrophenol to aminophenol.

B.B.VIII.3
09:30
Authors : Jens Eriksson1, Donatella Puglisi1, Hossein Fashandi1, Mike Anderson1, Rositza Yakimova1-2, Anita Lloyd Spetz1
Affiliations : 1 Department of Physics, Chemistry, and Biology, Linköping University, 58183, Sweden; 2 Graphensic AB, SE-58333 Linköping, Sweden

Resume : Graphene-based gas sensors normally show ultra-high sensitivity to certain gas molecules while suffering from poor selectivity and slow response and recovery. Graphene functionalization can improve these issues but usually results in poor reproducibility. We report on surface modifications of epitaxial graphene on SiC with metal or metal-oxide nanostructures, formed by highly reproducible thin film deposition techniques, and their effect on the electronic properties of the graphene and on gas interactions at the graphene surface. Under the right decoration conditions the electronic properties of the surface remain those of graphene, while the surface chemistry can be modified to improve sensitivity, selectivity and speed of response toward e.g. nitrogen dioxide (NO2) or certain toxic volatile organic compounds (VOCs). Sensors with extremely low detection limits, selective towards these gases, can be useful for air quality control due to the high toxicity already at parts per billion (ppb) concentrations. The effect of decoration strongly depends on the choice, thickness and nanostructure of the material. Decoration with thin nano-porous Au allows reaching a NO2 detection limit below 1 ppb. Preliminary results indicate that decoration with TiO2 quantum dots can be used to selectively detect ppb concentrations of certain toxic VOCs. The presentation will include early results on other monolayer modifications of gas sensing layers like iron oxide on top of platinum.

B.B.VIII.4
14:00
Authors : A. C. Catto, L. F. da Silva, C. A. Escanhoela Jr, V. R. Mastelaro, S. Bernardini, K. Aguir,
Affiliations : Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil Instituto de Química, Universidade Estadual Paulista, Araraquara, SP, Brazil CNRS, IM2NP (UMR 7334), Aix-Marseille Université, 13397, Marseille, France

Resume : In the last years, the ozone gas sensors have been the subject of great attention for monitoring and determination of ozone gas concentration due to its high toxicity and effects to human health. Therefore the determination and continuous monitoring of ozone concentration has taken special interest in the last years due to its high toxicity and effects to human health. The zinc oxide (ZnO) compound is one of the most promising metal oxide for gas sensing applications due to the well-known high surface-to-volume and surface conductivity . Additionally, ZnO compound has been proved to be an excellent gas-sensing material for several gases, such as CO, NOx, ozone and ethanol. In this context, specials ZnO microstructures with different morphologies and high surface/volume ratio can overcome the limitations of the current commercial sensors. Motivated by these considerations, the goal of this study consisted to synthesize ZnO nanorods directly onto a SiO2/Si substrate with interdigitated Pt electrodes via hydrothermal method and evaluated its potential use as ozone gas sensor. In this study, we investigated the ozone sensing properties of as-prepared ZnO nanorods-like structures grown directly onto a substrate containing electrodes via hydrothermal method. The sensor response was studied for ozone concentration ranges from 0.08 ppm to 1 ppm at different operating temperatures. The ZnO nanorods displayed a short response time of 25 s and a recovery time of 88 s when exposed to 1 ppm of ozone at 250°C. Our results indicate that ZnO nanorods show a good sensitivity to the presence of ozone, even when exposed to a low concentration (0.08 ppm).

B.B.PII.7
14:00
Authors : F.Shao1, F.Hernández-Ramírez1 2, J.D. Prades2, N. López3, C.Fàbrega1, T. Andreu1, J.R.Morante1 2
Affiliations : 1 Catalonia Institute for Energy Research (IREC), E-08930 Sant Adrià del Besòs, Spain; 2 Department of Electronics, University of Barcelona, E-08028 Barcelona, Spain; 3 Institute of Chemical Research of Catalonia, ICIQ, Av. Països Catalans 16, 43007 Tarragona, Spain

Resume : CuO nanowires (NWs) were successfully obtained by the thermal oxidation of Cu foils. Their electrical properties were evaluated at individual level and they were integrated in conductometric gas sensing devices. This p-type metal oxide exhibited a higher sensitivity to ammonia (NH3) than the previously reported for n-type SnO2 NWs, while the accurate analysis of the response to oxidizing and reducing gases revealed that oxygen species at the surface play a key role in their sensing mechanisms

B.B.PII.9
 
Modelling of Sensors and Sensor/Gas Interaction : Albert Romano-Rodriguez, UB, Barcelona, Spain
14:00
Authors : Feng Shao1, Martin W. G. Hoffmann1 2, Joan Daniel Prades2, Joan Ramon Morante1 2, Núria López3, Francisco Hernández-Ramírez1 2
Affiliations : 1 Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, 08930 Sant Adrià de Besòs, Barcelona, Spain; 2 Department of Electronics, University of Barcelona, Marti i Franquès 1, 08028 Barcelona, Spain; 3 Institute of Chemical Research of Catalonia, ICIQ, Av. Països Catalans 16, 43007 Tarragona, Spain

Resume : In this work, the adsorption of NH3 on SnO2 was examined by density functional theory (DFT) calculations and confronted to experimental data obtained with individual nanowire devices. We demonstrated that the sensing process of ammonia on tin oxide nanowires not only involves physical mechanisms but also has a concomitant chemical nature that requires two molecules of NH3 for the reaction to take place. Our theoretical modeling also revealed why ammonia sensing is competitive to the adsorption of water molecules. As a result, interfering effects in monitoring traces of NH3 intrinsically occur in humid air.

B.B.PII.10
14:00
Authors : F. Shao a b, M.W.G. Hoffmann a b f, J.D. Prades b, R. Zamani a c, J. Arbiol c d, J.R. Morante a b, E. Varechkinae, M. Rumyantseva e, A. Gaskov e, I. Giebelhaus f, T. Fischer f, S. Mathur f, F. Hernández-Ramírez a b
Affiliations : a Catalonia Institute for Energy Research (IREC), Barcelona, Spain; b Department of Electronics, University of Barcelona, Barcelona, Spain; c Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus de la UAB, Bellaterra, Spain; d Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain; e Chemistry Department, Moscow State University, Moscow, Russia; f Institute of Inorganic Chemistry, University of Cologne,Cologne, Germany

Resume : In this work, p-CuO (particle)/n-SnO2 (nanowire) heterostructures were evaluated as selective H2S sensors, and the working principle behind their good performance was qualitatively modeled. It was concluded that the main sensing mechanism is dissimilar to standard redox reactions typical of regular metal oxide (MOX) devices, and it can be ascribable to the sulfurization of CuO and the consequent variation of the p-n junction structure at the CuO-SnO2 interfaces. Experimental data showed that these individual nanowire H2S sensors suit well for alarm applications with extremely high selectivity and sensitivity to this gas for concentrations between 1 ppm and 10 ppm.

B.B.PII.11
14:00
Authors : Won Suk Chang1, Jung Hyun Kim1, Daeho Kim1 3, Seung Kwon Seol1 2
Affiliations : 1Nano Hybrid Technology Research Center, Korea Electrotechnology Research Institute (KERI), Changwon 642-120, KOREA;2Electrical Functionality Material Engineering, University of Science and Technology (UST), Changwon 642-120, KOREA;3Energy and Power Conversion Engineering, University of Science and Technology (UST), Changwon 642-120, KOREA

Resume : Conducting polymers such as polypyrrole (PPy), polyaniline (Pani), Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and their derivatives are very interesting materials because they combine tunable electrical transport characteristics and excellent mechanical properties. In particular, conducting polymers have been used as the active parts of gas sensors since early 1980s [1]. In comparison with most of the commercially available sensors, based usually on metal oxides and operated at high temperatures, the conducting polymer sensors have many improved characteristics. They have high sensitivities and short response time; especially, these feathers are ensured at room temperature. In this study, we fabricated a sensitive wire transducer in a chemiresistive gas sensor by a three-dimensional (3D) growth of PEDOT:PSS wires with arched shape. The wires were grown by controlled pulling of a micropipette (?Fountain-pen?) filled with a PEDOT:PSS solution (?Ink?) [2,3]. When the fountain-pen touched the substrate, a meniscus of the ink was created outside its opening and the solvent was evaporated at the same time. As the fountain-pen was pulled away, the meniscus was stretched and its cross section decreases, resulting in formation of wires. The individual positioning of grown wires was easily available by the 3D accurate control of fountain-pen. The as-prepared suspended PEDOT:PSS sensor which consisted of 10 wire array was tested for their ability to sense water, ethanol and acetone vapor gases at the room temperature. The sensor showed high sensitive, rapid, stable and reversible responses for detection of various concentrations of vapor gases, resulting from high surface area to volume ratio of the suspended wire. KEYWORDS Conducting polymer nanowire, Gas sensor, 3D suspended wire, Fountain-Pen lithography, Direct writing REFERENCES [1] Nylabder, C.; Armgrath, M.; Lundstrom, I., Proceedings of the International Meeting on Chemical Sensors, Fukuoka, Japan, 203 (1983). [2] Ji Tae Kim, Seung Kwon Seol, Jaeyeon Pyo, Ji San Lee, Jung Ho Je and G. Margaritondo, Advanced Materials 23 1968 (2011). [3] Seung Kwon Seol, Daeho Kim, Sunshin Jung and Won Suk Chang, RSC advances 2 8926 (2012).

B.B.PII.13
14:00
Authors : 1) T. Mazingue, M. Lomello-Tafin, M. Passard, L. Goujon, C. Hernandez-Rodriguez, 2) J.-L. Rousset, F. Morfin, 3) G. Maulion, R. D. Kribich, 4) P. Coudray, 5) T. Wood, J. Le Rouzo, F. Flory 6) J.-F. Laithier
Affiliations : 1) Université de Savoie, Laboratoire SYMME, BP 80439, 74944 Annecy le Vieux Cedex, France ; 2) Institut de Recherches sur la Catalyse et l’Environnement de Lyon IRCELYON, CNRS-University of Lyon 2 avenue Albert Einstein, F-69626 Villeurbanne Cedex, France ; 3) Université Montpellier II, Institut d’Électronique du Sud – IES, UMR CNRS/UM2 5214, Place Eugène Bataillon, 34095 Montpellier, France ; 4) Kloé SA, Hôtel d’Entreprise du Millénaire, 1068 Rue de la Vieille Poste, 34000 Montpellier, France ; 5) Aix-Marseille Université, Institut Matériaux Microélectronique Nanosciences de Provence – IM2NP, CNRS-UMR 7334, Domaine Universitaire de Saint-Jérôme, Service 231, 13397 Marseille, France ; 6) Comelec SA, Rue de la Paix 129 - CH-2301 La Chaux-de-Fonds, Switzerland

Resume : Increasingly restrictive limitations of pollutants require the development of more accurate detection devices. Although there are already a large number of sensors from mature technologies currently on sale, the detection of some gases remains problematic (limit of detection, time response, repeatability, cross-sensitivity, ...). We present here the main results of the PEPS (PEllet Photonic Sensor) project, aiming at developing a new transducer via a technological breakthrough : the combination of photonics (insensitive to external electromagnetic disturbances and deportation of the measurement fiber optic components) and catalysis (reversibility, limited energy consumption). Indeed, catalytic reaction are often exothermic and this heat of reaction can modify the properties of optical devices. The experimental studies performed during the PEPS project highlighted the rapid and reversible response at room temperature of catalytic powders towards different concentrations of CO and H2. The thermal and optical properties of the materials used for the photonic component have also been studied. These results have been exploited for the design of the photonic transducers. The feasibility of the physical transduction principle has been demonstrated by developing different prototypes based on Bragg gratings and Multimode Interference Couplers.

B.B.PII.19
14:00
Authors : Camelia FLORICA (a), Elena MATEI (a), Andreea COSTAS(a), Monica ENCULESCU(a), Maria Eugenia Toimil Molares (b), Ionut ENCULESCU (a)
Affiliations : (a) National Institute of Materials Physics, PO Box MG-7, 77125, Magurele-Bucharest, Romania; (b) GSI, Helmholtz Centre, Planck str. 1, D-64291, Darmstadt, Germany

Resume : Semiconductor ZnO nanowires(NWs) were prepared using the electrodeposition method in a polycarbonate template. By ultrasonication in alcohol the grown NWs were harvested and drop-casted on a SiO2/Si substrate. The optical, morphological and structural properties of the NWs were investigated. Photolithography and e-beam lithography were used for contacting single NWs. When Ti/Au metallic contacts were deposited on the NWs, ohmic electrical characteristics were obtained. Thus an appropriate framework was created for processing back gate field effect transistors, having as gate the N++ heavily doped Si substrate. The electrical measurements on the ZnO NW transistors have shown a clear increase of the source drain current with the voltage applied on the gate electrode. The parameters of the transistor were calculated and were highly improved when the surface of the NW was passivated with PMMA and AZ5214E. In this case the source drain I-V characteristics were saturating at higher applied voltages and the Ion/Ioff ratio was in the range of 10000 having a field effect mobility of about 100 cm2/(V•s). The characteristic parameters are among the highest reported in literature for such devices even when compared with NWs which were prepared by other methods, e.g. VLS or CVD. These highly sensitive, electrodeposited ZnO NW field effect transistors are excellent candidates for various sensor applications including here chemical or bio – molecules detection.

B.B.PII.21
14:00
Authors : T.-H. Nguyen(a,c), E. Chevallier(a), Cl. Beaubestre(c), C. Rivron(c), Y. Bigay(a), T.-H. Tran-Thi(c)
Affiliations : (a) ETHERA R&D, CEA-Saclay, Bât. 451, F-91191 Gif-sur-Yvette Cedex, France (b) Laboratoire d’Hygiène de la Ville de Paris, 11 rue Georges Eastman, 75013 Paris, France (c) CEA-Saclay, DSM/DRECAM/SPAM/Laboratoire Francis Perrin, URA CEA-CNRS 2453, 91191 Gif-sur-Yvette Cedex, France,

Resume : In swimming pools, chlorine (Cl2) is used as a disinfectant to minimize the risk to users from microbial contaminants. In water, Cl2 is transformed into HOCl which reacts with saliva, sweat, urine and skin, leading to the formation of several chloramines, such as monochloramine (NH2Cl), dichloramine (NHCl2) and nitrogen trichloride (NCl3). Because of its low solubility in water, NCl3 is essentially found in the air while NH2Cl preferentially remains in water. These compounds are toxic and their detection has become of great importance. However, there is currently no fast and selective method of measurement of NCl3 in the atmosphere nor of NH2Cl in water. The development of innovative chemical and colorimetric sensors for the direct detection of NCl3 and NH2Cl, is described. They are based on solid nanoporous materials synthesized via the sol-gel process. These materials display high adsorptive properties and the pores are tailored to become efficient nanoreactors. These nanoreactors, are designed to enhance a specific reaction between a probe molecule and NCl3 or NH2Cl, leading to coloured products. With matrices doped with NaI and Amylose, an NCl3 sensor is produced which can detect NCl3 at ppb level within 20 minutes in humid atmospheres (RH : 60-80 %) at ambient pool temperatures. The NCl3 concentration range covered is 5 to 250 ppb. For the detection of NH2Cl, the Berthelot reaction is exploited with the formation of a final blue-green product absorbing in the visible with a maximum centered at 640 nm. The NH2Cl sensor can measure NH2Cl in water with a detection limit of 0.1 µM (1.8 ppb). We will show the comparison of the sensors performance to the currently used, but indirect, methods during campaigns of measurements in swimming pools.

B.B.PII.23
14:00
Authors : T. Yamamoto1), H. Song1), J. Nomoto1), H. Makino1) and S. Kishimoto1,2)
Affiliations : 1)Kochi University of Technology; 2)Kochi National College of Technology

Resume : We have investigated hydrogen sensing of heavily Ga-doped ZnO (GZO) polycrystalline films. We deposited 50-nm-thick GZO films on glass substrates (@200 ºC) by ion-plating with dc arc discharge. A sintered ZnO tablet with a Ga2O3 content of 3 wt.% was used as a deposition source. Hall effect measurement results showed electrical resistivity of 2.36×10-3 Ωcm, carrier concentration of 1.89 ×1020 cm-3 and Hall mobility of 14.0 cm2/Vs. Analysis of data obtained by XRD measurements shows that the films consist of wurtzite structure with a preferred c-axis orientation perpendicular to the substrates. The gas sensing properties toward hydrogen gas (the concentration in air of 1 volume%) strongly depended on operating temperature. We found as follows: (1) a change in electric current of +0.1 to +0.2 mA at 150 ºC; (2) a change in electric current of -5.0 mA at 330 ºC. The findings imply that the gas sensing mechanism at the high operating temperature is significantly different from that at the low operating temperature. We will propose that the mechanism at the low temperature is limited by chemical reaction between hydrogen gas and oxygen atoms with a negative charge in the grain bulk, generating free carriers to increase carrier concentration, whereas a factor limiting the mechanism at the high temperature is concentration of hydrogen molecules physically adsorbed at the grain boundary, enhancing a barrier height to carriers at the grain boundaries to decrease carrier mobility.

B.B.PII.26
14:00
Authors : J.R. Sanchez-Valencia, M. Alcaire, P. Romero-Gómez, M. Macías-Montero, F.J. Aparicio, A. Borras, A.R. González-Elipe, A. Barranco
Affiliations : Consejo Superior de Investigaciones Científicas. Instituto de Ciencia de Materiales de Sevilla (CSIC-Universidad de Sevilla). c/Américo Vespucio 49, 41092 Sevilla, Spain.

Resume : ZnO is a fluorescence material characterized by one emission line in the near UV range of the spectrum associated with excitonic decay processes and a broad emission in the visible linked with electronic defects in the gap. It is recognized that the relative ratio between the excitonic and defect emissions depends on the crystallization and agglomeration states of ZnO. In this work we report the synthesis of ZnO nanocolumnar porous thin films by plasma enhanced chemical vapor deposition1 that, despite of their relatively porous character, only presenting an intense fluorescence emission at room temperature. It is found that the emission intensity is quite sensitive to the presence of oxygen in the medium and its evolution as a function of the oxygen concentration can be utilized for the photonic sensing of this gas in the environment. In addition, the system is also able to respond to the oxygen concentration dissolved in water and other liquid medium where the sensitivity of detection can be one or two order of magnitudes higher than that of commercial detectors based on electrochemical methods. The mechanism of detection and the development of a new generation of photonic sensors of oxygen based in pure ZnO are discussed. 1.- P. Romero-Gómez, J. Toudert, J.R. Sánchez-Valencia, A. Borrás, A. Barranco, A.R. González-Elipe. Journal of Physical Chemistry C 114, 20932–20940 (2010).

B.B.PII.29
14:00
Authors : Joe Briscoe, Sabina M. Hatch, Steve Dunn
Affiliations : Joe Briscoe, Steve Dunn: Queen Mary University of London, UK; Sabina M. Hatch: University College London, UK

Resume : UV photodetectors are used in many applications including biological and chemical analysis, flame sensing and astronomical studies. UV can be damaging to humans and many materials, but also can be used in air, water and food purification; therefore UV monitoring can be used to assess potential harm or to control dosing. UV photodetectors typically require an external bias, but for self-sufficient sensors systems power sources such as batteries add considerably to their size and weight, and integration of sensors into multi-component nanosystems will be facilitated by self-powered functionality. We present a self-powered UV detector using a p-n heterostructure of CuSCN and ZnO nanorods produced using low temperature solution methods. At a nominal zero-applied field, the device produces a photocurrent response of 4.5 µA for a low UV (375nm) irradiance of 6.0 mW/cm2. A fast 500 ns rise and 6.7 µs decay time was recorded with a UV/visible rejection ratio of ~100. With a small applied bias of +0.1 mV a rapid detection time of 4 ns was possible. For comparison to similar heterostructures a responsivity of 9.5 A/W was measured at -5 V applied bias. The photodetector performance was attributed to the pre-existing Fermi-level alignment of the ZnO and CuSCN semiconductors, which resulted in a low turn-on voltage of ~0 V and photovoltaic behaviour. Therefore the ZnO/CuSCN UV photodetector is suitable for nanoscale applications that require rapid response times and self-sufficiency.

B.B.PII.31
14:00
Authors : J. Sama 1, S. Barth 2, J.D. Prades 1, O. Casals 1, I. Gracia 3, C. Cané 3, A. Romano-Rodríguez 1
Affiliations : 1 MIND-IN2UB-Dept. Electronics, Universitat de Barcelona (UB), Martí i Franquès 1, 08028, Barcelona, Spain; 2 Institute of Materials Chemistry, TU Wien, Getreidemarkt 9/165, A-1060 Vienna, Austria; 3 Institut de Microelectrònica de Barcelona, IMB-CNM-CSIC, 08193 Bellaterra, Spain

Resume : Nanowires (NWs) have emerged as an important topic of research due to their high aspect ratio, and their capability to be part of new device architectures. Especially monocrystalline materials are important to achieve effective and known interactions of their surface in several applications, like gas sensors. An imporante issue that prevents the use of the nanostructures in functional electronic devices is their integration into a scalable process. Here we present a method for localized site selective direct growth of inorganic NWs that avoids several technological steps, reducing uncertainty factors of the process fabrication. VLS growth of SnO2 NWs is developed on top of CMOS compatible micromembranes with top interdigitated electrodes and buried integrated heater, which provides the thermal energy required for the growth. The SnO2 NWs show high crystalline quality and once the growth is finished, no post-processing is required because of NW bundles bridge the interdigitated contacts on top of the membrane. Thus, a scalable and time efficient process has been developed. The one-step fabrication device has been proven as a low power gas sensor, showing high response levels and low response times towards CO, NH3 and NO2 in a synthetic air atmosphere. The obtained devices will be shown as suitable for environmental gas sensing monitoring. The fabrication methodology will be described and its extension to the growth of other materials will be critically discussed.

B.B.PII.32
14:00
Authors : Albert Romano-Rodriguez 1, Jordi Sama 1, J. Daniel Prades 1, O. Casals 1, Francisco Hernandez-Ramirez 1 2, Sven Barth 3
Affiliations : 1 MIND-IN2UB-Dept. Electronics, Universitat de Barcelona (UB), Martí i Franquès 1, 08028, Barcelona, Spain; 2 Institut de Recerca en Energia de Catalunya (IREC), E-08930 Sant Adrià de Besós, Spain; 3 Institute of Materials Chemistry, TU Wien, Getreidemarkt 9/165, A-1060 Vienna, Austria

Resume : Semiconducting nanowires (NW) are very attractive materials for gas sensing applications due to their high aspect ratio, that results in strong interactions between their surface and the surrounding atmosphere, giving rise to important electrical changes in the nanomaterial. Heating the NW is required to reach the right operation temperature. When operating with one single NW, the same current that is used to measure the resistance can be used to provide the NW heating, dramatically reducing the power consumption of the device. Here we present a single metal oxide nanowire gas sensor with ultra low power consumption based on this principle. Defect-free monocrystalline SnO2 nanowires were synthesized by chemical vapor deposition of a molecular precursor [Sn(OtBu)4]. NWs were dispersed onto a substrate with prepatterned electrodes and a Focused Ion Beam machine equipped with a Pt precursor was used to contact the individual NW to the electrodes. Very low level of currents, below of 1 µA, are enough to bring the nanomaterial to temperatures in excess of 150ºC, at which the reaction between surface adsorbed oxygen and reducing or oxidizing species takes place, while allowing the resistance variation to be measured. High response and low response times have been obtained against NO2, and a mixture of NO2 with humidity in a synthetic air atmosphere. The advantages and drawbacks of the approach to develop these advanced ultra-low power consumption gas sensors will be discussed.

B.B.PII.33
14:00
Authors : O.Monereo, G. Vescio, S. Claramunt, O. Casals, J.D. Prades, A. Cirera, A. Cornet
Affiliations : MIND/IN2UB Electronics Department, Universitat de Barcelona, Spain

Resume : One of main advantages of carbon based sensors is their low temperature of operation, compared with materials such as metal oxides [1]. Among carbon materials, carbon nanofibers (CNFs) show very attractive properties for environmental gas sensing [2], at a moderate production costs. However, the knowledge about the sensing mechanisms in this material is very limited. In this work, we study of the interference of water and oxygen on the response of CNFs conductometric gas sensor, at different operation temperatures (<150ºC), and under ultraviolet light. From a fundamental perspective, our results show that, at different working conditions, different competitive mechanisms between both species on the CNFs surfaces occur. From a practical perspective, our experiments confirmed that at low temperatures (<80ºC) and low ultraviolet light intensities, CNFs are suitable for environmental relative humidity sensing. Moreover, the baseline and the responses of these sensors were highly stable and reproducible, even after several weeks of operation. The here-studied sensors were fabricated with a combination of inkjet printing and electrospray technique over flexible substrates [3]. [1] M. Penza, R. Rossi, M. Alvisi, D. Suriano, E. Serra, Pt-modified carbon nanotube networked layers for enhanced gas microsensors, Thin Solid Films. 520 (2011) 959–965. [2] O. Monereo, S. Claramunt, M.M. De Marigorta, M. Boix, R. Leghrib, J.D. Prades, et al., Flexible sensor based on carbon nanofibers with multifunctional sensing features., Talanta. 107 (2013) 239–47. [3] S. Claramunt, O. Monereo, M. Boix, R. Leghrib, J.D. Prades, a. Cornet, et al., Flexible gas sensor array with an embedded heater based on metal decorated carbon nanofibres, Sensors Actuators B Chem. 187 (2013) 401–406.

B.B.PII.34
14:00
Authors : O.Monereo, S. Claramunt, G. Vescio, O. Casals, J.D. Prades, A. Cirera, A. Cornet
Affiliations : MIND/IN2UB Electronics Department, Universitat de Barcelona, Spain

Resume : To achieve good sensing performance, in terms of response time, reversibility and baseline stability, normally imply, conductometric solid-state gas sensors require and external an external source of energy, capable of stimulating the solid-gas interactions[1]. Ultraviolet light (UV) [3] is a viable alternative to the traditional strategy of heating the sensor material [2]. Here, we present a study on the use of UV to modulate the response of flexible gas sensors based on carbon nanofibers (CNFs). The sensing device was developed with a combination of different methods including the inkjet printing for the fabrication of the electrodes and electrospray technique for the deposit of the sensing material [4]. UV illumination was chosen first, to anneal the active layer in the fabrication process and then, to fasten desorption of the gas adsorbed, achieving a stable sensor signal. UV light was also proven to be an effective method to improve reversibility and response dynamics. In comparison with temperature modulation, UV illumination seems to be much more effective to improve the sensing characteristics. Characterization on the modulation of UV light was performed, focusing in the sensing of NH3 and NO2. Sensor response, response time and recovery time were fully characterized. A sensing mechanism is proposed in order to explain and verify the behavior of the CNFs sensor. NH3 and NO2 sensing is proven to be achievable with the correct UV light modulation. [1] Z. Zanolli, R. Leghrib, A. Felten, J.-J. Pireaux, E. Llobet, J.-C. Charlier, Gas sensing with Au-decorated carbon nanotubes., ACS Nano. 5 (2011) 4592–9. [2] J.D. Fowler, M.J. Allen, V.C. Tung, Y. Yang, R.B. Kaner, B.H. Weiller, Practical chemical sensors from chemically derived graphene., ACS Nano. 3 (2009) 301–6. [3] P. Qi, O. Vermesh, M. Grecu, A. Javey, Q. Wang, H. Dai, et al., Toward Large Arrays of Multiplex Functionalized Carbon Nanotube Sensors for Highly Sensitive and Selective Molecular Detection, Nano Lett. 3 (2003) 347–351. [4] S. Claramunt, O. Monereo, M. Boix, R. Leghrib, J.D. Prades, a. Cornet, et al., Flexible gas sensor array with an embedded heater based on metal decorated carbon nanofibres, Sensors Actuators B Chem. 187 (2013) 401–406.

B.B.PII.35
14:00
Authors : M. Braik, C.Dridi, M. Ben Ali A. Ali, M. Abbes, M. Zabala, J. Bausells, N. Zine, N. Jaffrezic-Renault, A. Errachid
Affiliations : Université de Sousse, ISSAT de Sousse, Cité Ettafala, 4003 Ibn Khaldoun Sousse, Tunisia / Université de Monastir, LIMA, Faculté des Sciences de Monastir, 5019 Monastir, Tunisia / Analytical Laboratory, Department of Applied Organic Chemistry, National Research Centre, Cairo, Egypt / Centro National of Microelectronica (IMB-CSIC), Campus UAB, 08193 Bellaterra, Barcelona, Spain / Institut des Sciences Analytiques (ISA), Université Lyon, Université de Claude Bernard Lyon 1, UMR 5280, 5 rue de la Doua, 69100 Villeurbanne, France

Resume : Capacitive-voltage measurement (C(V)), as one of the most sensitive electrochemical methods, has been investigated extensively for the detection of environmental contaminants in recent years. In this work, we reported the development of a chemical sensor based on Co(II) phthalocyanine acrylate-polymer (CPAP) as a sensitive membrane for detection perchlorate anions. For this, we have used two type of transducer, silicon nitride (Si3N4) and Hafnium oxide (HfO2) grown by Atomic Layer Deposition (ALD) on silicon [1,2]. High dielectric constants of the produced HfO2 film facilitated the processing of the chemical sensor with considerably higher input capacitances than the standard Si3N4. The surface qualities of the used transducers have been studied by contact angle measurement. We have studied the pH effect on Si/HfO2/Electrolyte capacitance values for different phosphate buffer solutions (PBS). This optimization step have allowed a sensitivity value of about 46 mV/decade. We have developed also a perchlorate sensors based on Si3N4 and HfO2 transducers functionalized with CPAP membrane and characterized by C(V) measurements for different perchlorate concentrations (from 10-7 to 10-2 M). The sensor developed with HfO2 transducer shows better performances compared to that based on Si3N4 : a larger detection range (10-6 - 10-2 M and 10-4 - 10-2 M respectively) and a lower detection limit (10-6 M and 10-4 M). The specificities of our perchlorate sensor has been tested for some interfering ions (nitrate, sulfate and carbonate).

B.B.PII.36
14:00
Authors : Filippo Fedi1, Filiberto Ricciardella2-3, Maria Lucia Miglietta2, Tiziana Polichetti2, Ettore Massera2 and Girolamo Di Francia2
Affiliations : 1 CNR-Institute for Composite and Biomedical Materials, Piazzale E. Fermi 1, Portici (Naples), I-80055, Italy; 2ENEA UTTP-MDB Laboratory, R.C. Portici, Piazzale E. Fermi 1, Portici (Naples), I-80055, Italy 3University of Naples ‘Federico II’, Department of Physics, Via Cinthia, I-80126, Naples, Italy

Resume : Solid-state gas sensors operating in environmental conditions generally suffer from slow and incomplete recovery to the initial value after the sensing signal. There is therefore a general request to develop a fast and efficient way aimed to restore the sensor. In the case of graphene-based chemiresistors used for NO2 detection, for example [1], it has been observed a poisoning effect on the material due to a simple environmental air exposure for >48h or to repeated exposure cycles. As a result, the sensing response shows smaller and smaller changes in conductance value. In this work we present a method to restore the exhaust chemiresistors that relies on the water capability to remove the adsorbed NO2[2]. Besides we report on the development of a simple and fast signal processing analysis to overcome the incomplete recovery. Colloidal suspension of graphene were prepared with liquid phase exfoliation (LPE) of graphite flakes in NMP [3,4]. Chemiresistor devices were prepared by drop-casting few microliters of graphene dispersions onto a transducer made with Au interdigitated electrodes printed on an Alumina substrate. After the preparation, a chemiresistor was mounted in a Gas Sensor Characterization System (GSCS) and exposed for 10 minutes to a flow of 350 ppb of NO2 in nitrogen (at T=25°C and relative humidity RH=50%) [1]. A conductance change as high as 27% was recorded highlighting a very high sensitivity to the analyte. The sensitivity completely dropped after the exposure to environmental air for more than one month. Exhaust chemiresistors were then dipped in water for one minute at high temperature (95°C) in order to increase the kinetics of the solubility process and dried at 150°C for few minutes in air. The device conductance was seen to enhance by more than 33% after the recovery treatment. The exceptionally high response obtained suggests that water was effective in removing the groups that pollute the transducers. On the other hand, the improvement of the sensing properties can be also hypothesized as due to the water treatment that was able to remove residues of the organic solvent employed in the graphene solution as well as to clean out the film surface. In summary, test results show that this recovery method is effective and could be profitable exploited to process exhaust sensing materials.

B.B.PII.38
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09:00
Authors : Aristizabal, N., Ríos, X., Echeverría, J.C., Garrido, J.J.
Affiliations : Departamento de Química Aplicada. Universidad Pública de Navarra. Campus Arrosadía, 31006 Pamplona. Spain.

Resume : Research on sensing mechanisms and vapor-surface interaction is the key for developing FOs to detect VOCs in environment, healthcare, food quality, and industrial process control. So far, research on FOs has focused on the configuration and the films used as sensing elements. Less attention has been paid to the effect of temperature and the interaction of VOCs with the surface of films. We report experimental results on the effect of temperature in the range 5 – 50 ºC on the response of FOs that uses films of hybrid silica xerogels as the sensing elements. The xerogel films were prepared using the sol-gel process at pH 4.5 using mixtures of methyltriethoxysilane (MTEOS) or ethyltriethoxysilane (ETEOS), and tetraethylorthosilane (TEOS) in a 30:70 molar percentage, and affixed to the end of the optical fiber by the dip-coating technique. The measuring system works under volumetric static conditions. In the range 20 – 40 ºC, the response decreased with temperature, which can be attributed to the decrease in the adsorption of VOCs, which is an exothermic process. Below 20 ºC the response didn’t change with temperature that can be mainly attributed to the condensation of the analytes in the film. For temperatures higher than 45 ºC, adsorption is scarce. At a given temperature, experimental data agree with a model based on adsorption of VOCs molecules on the films that, in turn, changes the refractive index of the external medium. The interaction energy (Ea) was obtained by applying the Arrhenius equation to the experimental data in the range 20 – 40 ºC.

B.B.X.2
 
Catalytic Chemical Sensing Materials : Bilge Saruhan-Brings, German Aerospace Center (Germany) and Martin Eickhoff, Justus Liebig University of Giessen (Germany)
10:30
Authors : Ehsan Danesh , Krishna C. Persaud
Affiliations : School of Chemical Engineering and Analytical Science, The University of Manchester, UK

Resume : Ammonia is a chemical that is encountered in many different environments over a wide range of concentrations. Sensors are required that can cover a large dynamic range of concentrations. For instance, ammonia levels in the natural atmosphere can be very low, down to sub-ppb concentration. Hence, very accurate ammonia detectors with a detection limit of 1 ppb or lower are required for measuring such concentrations. On the other hand, near intensive farming areas, ammonia concentrations are much higher, above 10 ppm. The sensors need to work under high background humidity and under a range of temperature. Polyaniline has good (thermal/environmental) stability and provides reasonable conductivities required for most application fields. The material can be reversibly doped and undoped by electrochemical or chemical oxidation or reduction. While this material has previously been used for chemical sensing of ammonia, problems of reversibility, and difficulties in making reproducible sensors have limited its use. Here we report the development of a vapour phase polymerisation technique that allows the deposition of nanolayers of polyaniline onto interdigited substrates where a heater is incorporated. The resulting structure forms a heated chemiresistor that has improved reproducibility in manufacture as well as good reversibility on binding ammonia. By adjusting the dimensions and thickness of the polymer layer, a large dynamic range of ammonia concentrations can be measured. We have eliminated the need for solubilising polyaniline, and the process is fully compatible with large scale fabrication methods including printing technologies.

B.B.XI.1
11:15
Authors : Davide Carboni, Luca Malfatti, Alessandra Pinna, Barbara Lasio, Yasuaki Tokudome, Masahide Takahashi, Plinio Innocenzi
Affiliations : a) Laboratorio di Scienza dei Materiali e Nanotecnologie, D.A.D.U., Universita` di Sassari, CR-INSTM, Palazzo Pou Salit, Piazza Duomo 6, 07041 Alghero, SS, Italy; b) Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan

Resume : Nowadays the increasing level of ground water contamination, due to highly toxic organic pollutants (HTOPs), such as the organophospate pesticides, is becoming a serious threat especially for the neurotoxic effects associated with some of them. This issue has therefore arisen the need for new catalytic materials with water remediation capabilities. The present work is aimed at developing a titania-based mesoporous film with catalytic properties toward organophosphate pesticides by combining two different approaches: the molecular imprinting and the self-assembly with a supramolecular template. The mesoporosity of the material has been obtained by using a tri-block copolymer (Pluronic F127) as a micellar template while the molecular imprinted cavities have been templated by a complex between La3 and bis-4-nitro-phenyl-phosphate. The template removal allowed opening, in one step, both the mesopores and the imprinted cavities with a simultaneous estimation of the active sites. The catalytic activity of the molecularly imprinted and not imprinted films toward the pesticide Paraoxon? has been evaluated by means of UV-Vis spectroscopy titration of the 4-nitro-phenolate released by the Paraoxon? hydrolysis. The analysis of the initial rates of molecularly imprinted and not imprinted films has shown that the presence of a very low number of molecular cavities improves the catalytic properties of the imprinted film when compared to the not imprinted films and the background hydrolysis

B.B.XI.3
11:30
Authors : 1) T. Mazingue, M. Lomello-Tafin, M. Passard, L. Goujon, C. Hernandez-Rodriguez, 2) J.-L. Rousset, and F. Morfin 3) J.-F. Laithier,
Affiliations : 1) Laboratoire SYMME, BP 80439, 74944 Annecy le Vieux Cedex, France 2) IRCELYON, CNRS-University of Lyon 2 avenue Albert Einstein, F-69626 Villeurbanne Cedex, France 3) Comelec SA, Rue de la Paix 129 - CH-2301 La Chaux-de-Fonds, Switzerland

Resume : Palladium Platine (PdPt) has been intensively studied these last decades due to high conversion rate in hydrogen oxidation at room temperature with significant exothermic effects (up to 250 KJ/mol). These remarkable properties have been studied by measuring the temperature variations of alumina (Al2O3) supported nanosized PdPt nanoparticles exposed to different hydrogen concentrations in dry air. This catalyst is expected to be used as a sensing material for stable and reversible ultrasensitive hydrogen sensors working at room temperature (low power consumption). Structural and gas sensing characterizations and catalytic activity of PdPt/Al2O3 systems synthesized by co-impregnation will be presented. Catalytic characterizations show that the system is already active at room temperature and sharply increases with rise in temperature. Moreover, the increase of the PdPt proportion in the co-impregnation process, improves the activity and very high conversion can be reached even at room temperature. The thermal response (about 3°C) of only 1 mg of PdPt/Al2O3 is reversible and the time response is about 5 seconds. The integration of PdPt/Al2O3 powder on a flat substrate has been realized by the deposition onto the powder of a thin porous hydrophobic layer of parylene. The possibility of using PdPt in gas sensors will be discussed.

B.B.XI.4
12:00
Authors : Madjid Arab1*, Nadine Dirany1, Ali Hallaoui1,2, Loic Patout1, Christine Leroux1, Jean Raymond Gavarri1
Affiliations : 1Université du Sud-Toulon Var, IM2NP, UMR CNRS 6242, BP 20132, 83957, La Garde, France 2 Université Ibn Zohr, LME, BP 32/S Agadir Maroc

Resume : In this study, we develop tungstate materials for nanostrucutre catalytic sensors systems allowing the detection of pollutant like as methane and carbon monoxide. We report the synthesis of WO3 and SrWO4 (SWO) phases, based on the coprecipitation approach. All samples were characterized by thermogravimetric analysis, X-ray diffraction and electron microscopy to identify the structure and the morphology of each compound. The catalytic reactivity of the samples was analyzed using a reactor coupled to a combined system of Fourier Transform Infrared spectrometer (FTIR) and Mass Spectrometer (MS) apparatus. The measurements were performed with different gas carriers, from room temperature to 600ºC. The catalytic activity was determined as a function of time, temperature and gases concentration. FTIR experiments show that methane given rise to two types of reactions, partial and total oxidation, at high temperature. Unlike to carbon monoxide, the oxidation occurs at a low temperature. The reactivity should be linked to oxygen species and electron exchanged with the solids. To try to connect catalytic senssing effects with charges mobility, electrical analyses have been performed. Electrical impedance measurements have been carried out on compacted polycrystalline samples, and have been interpreted with Nyquist representations.

B.B.XI.6
14:45
Authors : Amadou NDIAYE1,2, Jérôme BRUNET1,2, Michele Penza3, Alain PAULY1,2, Marco Alvisi3, Christelle VARENNE1,2
Affiliations : 1Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand, France 2 CNRS, UMR 6602, Institut Pascal, F-63171 Aubière, France 3 ENEA Technical Unit of Technologies for Materials, Brindisi Research Center, I-72100 Brindisi, Italy,

Resume : Research on carbon nanomaterials for applications covering electronics devices, chemical sensors etc [1] is becoming a flourishing domain. Owing to their narrow size, carbon nanotubes (CNTs) as a new class of carbon nanomaterials present noticeable properties mainly attributed to their high surface areas and their transport properties, leading especially to tailored surface reactivity. However, because of their poor solubility, CNTs have a restricted use in many applications. This problem can be overcome by functionalisation methods [2]. The functionalization is a good way for simultaneously preserving the CNTs properties and bringing additional functionalities like gas sensitivity. In this work, CNTs have been functionalized with conjugated organic molecules like phthalocyanines (Pcs) or porphyrins (Por) derivatives for potential application in the detection of BTX (Benzene-Toluene-Xylenes). With our strategy based on dispersion technique, sensing structures based on macrocycle-CNTs hybrid materials have been processed on different transducers. This presentation will be focussed on: the functionalization of the CNTs, their characterisations (UV-Vis spectroscopy, TGA, TEM, Raman analysis) and the room temperature sensitivity of these hybrids materials towards BTX and others interfering gases. References: [1] A.G. Mamalis et. al., Prec. Eng., 2004, 28, 16. [2] D.M. Guldi, et. al., Chem. Rev. 2010, 110, 6768.

B.B.XII.3
16:30
Authors : J. Samà1, S. Barth2, J.D. Prades1, M. Seifner2, O. Casals1, I. Gracia3, J. Santander3, C. Calaza3, L. Fonseca3, C. Cané3, A. Romano-Rodríguez1
Affiliations : 1 MIND-IN2UB-Dept. Electronics, Universitat de Barcelona (UB), Martí i Franquès 1, 08028, Barcelona, Spain; 2 Institute of Materials Chemistry, TU Wien, Getreidemarkt 9/165, A-1060 Vienna, Austria; 3 Institut de Microelectrònica de Barcelona, IMB-CNM-CSIC, 08193 Bellaterra, Spain

Resume : Germanium (Ge) is a classical semiconducting material that constituted the substrate for the invention of the bipolar transistor, but due to its low abundance at the earth crust it is only sparsely used for certain applications. However, recently, there is a growing interest on Ge nanowires (NW) because they overcome electrical and optical properties of silicon. In this work we present for the first time, to the best of our knowledge, the development and gas test of Ge nanowire based chemoresistive gas sensors. For this, we have locally, site-specifically and energy and material efficiently grown NWs using the VLS method on the top of micromembranes equipped with surface interdigitated electrodes and a buried heater. Similarly to other chemiresistors, the GeNW surface reacts with the presence of reducing and oxidizing gases, what causes a change in its resistance. A drawback of Ge is, unlike silicon, a non uniform and non stoichiometric GeOx layer is formed, whose thickness can be limited by working in a low temperature range. Ge NWs based sensors have shown good response towards the presence hundred of ppb’s of NO2 and CO even at room temperature. The fabricated device provides a functional sensor which consumes few mW for both heating and measuring. The behavior of the Ge NW gas sensor will be presented and the possibilities for improvements of its properties through surface functionalization will be discussed.

B.B.XIII.2
18:00
Authors : Hossam Haick
Affiliations : The Department of Chemical Engineering and Russell Berrie Nanotechnology Institute, Technion ? Israel Institute of Technology, Haifa 3200003, Israel

Resume : We have developed an ultra-sensitive, multi-parametric touch (or pressure) flexible sensors based on monolayer-capped nanoparticles (MCNPs). These sensors can be produced through SINGLE fabrication step and can be operated under low power consumption (0.5 V) and extreme environmental confounding factors (e.g., high humidity levels and contaminants in the atmosphere). On top of these attributes, we were able to build an MCNP-based prototype allowing simultaneous detection and monitoring of multiple environmental parameters of touch (or pressure), humidity, and temperature. These devices have shown the ability to decouple between the various stimuli (e.g., pressure, temperature, and humidity) that exist in a complex mixture and/or environment, which, so far, represents a critical challenge for these multi-parametric sensors. Indeed, these multi-parametric sensors have shown abilities to sense temperature with resolution higher than 1 ?C and average error of ~5%, relative humidity with resolution higher than 1% RH and average error of ~2% and pressure/touch with a resolution of 0.2gr. Overall, these sensors have shown excellent potential for future robust, simple, large-area, cost-effective and easy-to-fabricate bendable and stretchable sensing systems that can be utilized in a wide variety indoor and outdoor environmental monitoring applications.

B.B.XIII.8

No abstract for this day