Flexible transparent sensors from reduced graphene oxide micro-stripes fabricated by convective self-assembly

International audienceReduced graphene oxide (rGO) currently represents an attractive alternative material for graphene and its already well-known electronics applications. Due to its liquid phase processing it can be produced inexpensively on large scale, but its deposition into films/patterns of defined geometry on solid substrates remains challenging. In this work, rGO micro-stripes with controlled morphology are prepared on polyethylene terephthalate substrates by Stop&Go Convective Self-Assembly. This method allows the deposition of regular arrays of rGO stripes by independently adjusting the stripe geometry and array period in an inexpensive, clean and fast way, and without any lithographic patterning. The as-obtained rGO stripes are highly transparent, flexible and good electrical conductors, properties which are of great value for future electronic devices. We exploit these properties for fabricating for the first time a bi-functional strain and humidity sensor which is optically transparent

Flexible transparent sensors from reduced graphene oxide micro-stripes fabricated by convective self-assembly

International audienceReduced graphene oxide (rGO) currently represents an attractive alternative material for graphene and its already well-known electronics applications. Due to its liquid phase processing it can be produced inexpensively on large scale, but its deposition into films/patterns of defined geometry on solid substrates remains challenging. In this work, rGO micro-stripes with controlled morphology are prepared on polyethylene terephthalate substrates by Stop&Go Convective Self-Assembly. This method allows the deposition of regular arrays of rGO stripes by independently adjusting the stripe geometry and array period in an inexpensive, clean and fast way, and without any lithographic patterning. The as-obtained rGO stripes are highly transparent, flexible and good electrical conductors, properties which are of great value for future electronic devices. We exploit these properties for fabricating for the first time a bi-functional strain and humidity sensor which is optically transparent

Enhanced electrocatalytic activity of PtRu/nitrogen and sulphur co-doped crumbled graphene in acid and alkaline media

International audienceThe low mass activity and high price of pure platinum (Pt)-based catalysts predominantly limit their large-scale utilization in electrocatalysis. Therefore, the reduction of Pt amount while preserving the electrocatalytic efficiency represents a viable alternative. In this work, we prepared new PtRu2 nanoparticles supported on sulphur and nitrogen co-doped crumbled graphene with trace amounts of iron (PtRu2/PF) electrocatalysts. The PtRu2/PF catalysts exhibited enhanced electrocatalytic performance and stability for the hydrogen evolution reaction (HER) at pH - 0. Moreover, the prepared PtRu2/PF electrocatalyst displayed higher HER activity than commercial 20% Pt/C. The PtRu2/PF catalyst achieved a current density of 10 mA cm-2 at an overpotential value of only 22 mV for HER, performing better activity than many other Pt-based electrocatalysts. Besides, the PtRu2/PF revealed a good performance for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline media. The PtRu2/PF catalyst recorded a current density of 10 mA cm-2 at an overpotential of only 270 mV for OER in KOH (1.0 M) solution and an onset potential of 0.96 V vs. RHE (at 1 mA cm-2) for ORR in KOH (0.1 M) solution