Pillared carbon@tungsten decorated reduced graphene oxide film for pressure sensors with ultra-wide operation range in motion monitoring

Flexible pressure sensors hold great potential in wearable and artificial intelligence devices. The reduced graphene oxide (rGO) film, as a candidate material for flexible pressure sensors, has the advantage of excellent electronic, mechanical and thermal properties along the in-plane direction. Unfortunately, rGO films exhibit non-ideal structural stability and thermal conductivity along the out-of-plane direction, which poses great challenges in engineering applications. In this work, a "bulk-like" model of alternating reduced graphene oxide/pillared carbon (rGO/PC) layers is built and analyzed through Density Functional Theory (DFT) calculations. Then, theoretical modeling is constructed to provide guidance for the design of a mini-sized, light-weight but high-performance pressure sensor. The rGO/PC-based pressure sensor (rGO/PC-PS) shows extraordinary performances, with high sensitivity of 0.41 kPa(-1), ultra-wide operation range (2 kPa-1200 kPa), impressively long durability of 10000 cycles and high working frequency. Electrically and thermally conductive tungsten (W) atoms are deposited on the surface of the rGO/PC film, greatly improving the sensitivity of the rGO/PC/W-based pressure sensor (rGO/PC/W-PS) up to 6.03 kPa(-1) at 1300 kPa. Moreover, the rGO/PC/W-PS can be used for weight monitoring, temperature conversion, speech recognition and gripping strength visualization, illustrating its great application potential in the fields of biomedicine and human-machine interaction. (C) 2021 Elsevier Ltd. All rights reserved.