We describe a process allowing the patterning of fully stretchable organic electrochemical transistors (OECTs). The device consists of an active stretchable area connected with stretchable metallic interconnections. The current literature does not provide a complete, simple and accurate process using the standard thin film microelectronic techniques allowing the creation of such sensors. An innovative patterning process based on the combination of laser ablation and thermal release tape ensures the fabrication of highly stretchable metallic lines – encapsulated in polydimethylsiloxane – from conventional aluminium tape. State-of-the-art stretchability up to 70% combined with ultra-low mOhms resistance is demonstrated. We present a photolithographic process to pattern the organic active area onto stretchable substrate. Finally the formulation of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) is tuned to achieve an OECT with a maximum stretchability of 38% while maintaining transconductance up to 0.35 mS and channel current as high as 0.2 mA.

International audienceNanostructured silicon-based materials are good candidates for thermoelectric (TE) devices due to their low thermal conductivity, customizable electrical conductivity, and reduced cost. Generally, nanostructured TE bulk materials are obtained through compaction and sintering at high temperature (>1000 °C) of silicon nanoparticles (NPs). In order to introduce TE generators in flexible electronic devices, development of thin film TE is needed. Inkjet-printing of silicon NPs-based ink is an interesting technology for this targeted application due to its low cost and additive process. This paper presents the implementation of inkjet-printing of a silicon NPs-based ink toward the fabrication of TE material on flexible substrate and the development of a characterization method for this material. After printing, recovering of electrical properties through sintering is mandatory. Nevertheless, special care must be taken in order to keep thermal conductivity low and reduce the annealing temperature to allow the use of flexible substrates. The functional properties: electrical and thermal (measured by Raman spectroscopy), are studied as a function of the annealing process. Two types of annealing: rapid thermal annealing and microwave annealing, are investigated as well as two atmospheres: inert (N2) and reducing (N2-H2 5%)

The growing need for alternative sources to power Internet of Things and autonomous devices has led to many energy harvesting solutions from ambient energy sources. Use of batteries requires complementary energy source for extending the lifetime of the device. In recent times, triboelectric nanogenerators have gained significant attention in charging applications through ambient energy harvesting field due to their simplicity, efficiency and adaptability to many device configurations in nature. It is deemed to sustainably address power for autonomous smart applications in various environmental conditions. In this work, a state-of-the-art triboelectric nanogenerator based on wind actuated venturi design system is demonstrated in sync with the smart system evolution for powering various sensor nodal network. Using natural wind, the 3D printed wind actuated venturi triboelectric energy harvester converts ambient mechanical energy into electricity. This simple and compact device produces an optimum average power of 1.5 mW and produces a maximum output power density of 2850 mW.m-2 (peak power output of 4.5 mW), which is much higher than the existing reports that use larger surface area at higher wind velocity. Extensive material testing and future implementation in an array of applications aids for environment friendly energy production and increase the role of triboelectric nanogenerator in autonomous applications.

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