A tin dioxide (SnO 2) sensor was fabricated by inkjet printing onto polyimide foil. Gold electrodes and heater were printed on each side of the substrate. A SnO 2 based ink was developed by sol-gel method and jetted onto the electrodes. A final annealing at 400°C compatible with the polymeric transducers allowed to synthetize the SnO 2 sensing film. Electrical measurements were carried out to characterize the response of the fully printed sensors under oxidizing and reducing gases. The device was heated up at a temperature between 200 and 300°C using the integrated heater. The proper operation of the full printed metal-oxide gas sensors was validated under exposure to carbon monoxide and nitrogen dioxide, in dry and wet air.

International audienceFour cathode materials for single chamber solid oxide fuel cell (SC-SOFC) [La0.8Sr0.2MnO3-δ (LSM), Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF), Sm0.5Sr0.5CoO3-δ (SSC), and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF)] were investigated regarding their chemical stability, electrical conductivity, catalytic activity, and polarization resistance under air and methane/air atmosphere. Electrolyte-supported fuel cells, with Ce0.9Gd0.1O2-δ (CGO) electrolyte and a Ni-CGO anode, were tested in several methane/air mixtures with each cathode materials between 625 and 725 °C. These single cells were not optimized but only designed to compare the four studied cathodes. The decrease of methane-to-oxygen ratio from 2 to 0.67 strongly increased the performance of fuel cells for all cathode materials but the effect of temperature was not always significant. Cells with SSC, BSCF, and LSCF have shown a maximum power density about 20 mW cm-2 while the cell with LSM has given only 5 mW cm-2

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In recent years, printed and flexible gas sensors have quickly emerged as an innovative area of great interest because of their lightness and low cost.

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This paper presents a feasibility study on the development of a gas preconcentrator based on micro-reactor technology on silicon. The objectives are to select a gas adsorbent material, to produce a silicon micro-reactor with an integrated heater, and finally to introduce the most suitable adsorbent into the micro-channels of the device. Preliminary results related to the characterization of a carbon adsorbent for the development of a device for the preconcentration of benzene are reported. Carbon nano-powders have been tested as adsorbent material by the determination of the breakthrough time on a dedicated test bench consisting of gas sensors and a non-selective photoionization detector (micro-PID) analyzer. A fluidic deposition process allows filling up the silicon micro-channels with the carbon nano-powder. The interest in using porous silicon to enhance the binding of the carbon nano-particles in the micro-channels was also investigated. A silicon micromachined preconcentrator filled with 0.30 mg of commercial activated charcoal powder (Aldrich, 30-100 nm) was designed and built up. The total capacity of adsorption was determined by using the breakthrough time, which is of 2.2 min under a gas flow of 100 ppm of benzene at 1 l/h. Preliminary tests of preconcentration with 100 and 1.3 ppm benzene in dry air were performed.

Printed electronics, particularly on flexible and textile substrates, raised a strong interest during the past decades. This work presents a good candidate for conductive inks based on a graphene/polymer nanocomposite material that gathers three main benefits that are 1-neither clogging nor flocculation, 2-spontaneous film formation around room temperature, 3-high conductivity. Nanosized Multilayered Graphene (NMG) is produced through a solvent-free procedure, using a grinding process in water. These NMG suspensions are used to elaborate conductive composite materials through physical blending with emulsifier-free latex. The nanocomposite microstructure exhibits a well-defined cellular architecture that highlights the formation of continuous paths of fillers throughout the material. The conductivity behavior of the nanocomposite material was efficiently described using a percolation model: the conductivity can be tuned by changing the NMG content and the latex size. A low percolation threshold (0.1 vol%) was obtained and the electrical conductivity