Triboelectric touch sensor array system for energy generation and self-powered human-machine interfaces based on chemically functionalized, electrospun rGO/Nylon-12 and micro-patterned Ecoflex/MoS2 films

Highly tribopolar and minimized charge-loss tribolayers are great efficiency enhancers of triboelectric nanogenerators (TENGs). This study introduces two composite films to enhance the efficiency of TENGs: electrospun amino-functionalized reduced graphene oxide (A-rGO)/Nylon-12 and micropatterned molybdenum disulfide (MoS2)/Ecoflex as highly tribopositive and tribonegative layers, respectively. By incorporating A-rGO and MoS2 nanopillars into Nylon and Ecoflex, the positive and negative surface potentials increased by factors of 2.5 (from +350 V to +903 V) and 3.1 (from -433 V to -1352 V), respectively. The effects of the A-rGO and MoS2 contents on the TENG performance were investigated and optimized. The optimized TENG comprised a 2 wt. % A-rGO incorporated Nylon-12 (NY2) and 1.5 wt. % MoS2 embedded Ecoflex (EC1.5), exhibiting a maximum open circuit potential of 451 V, short circuit current of 13.3 µA, transfer charge density of 73.6 µCm-2 and instantaneous power density of 1.3 Wm-2 with a mechanical conversion efficiency of 96.7%. Furthermore, a flexible NY2/EC1.5 triboelectric sensor (TES) was fabricated without a spacer to obtain self-powered human-machine interfaces. The self-powered NY2/EC1.5-TES can detect and differentiate between various human motions, and a keyboard-based, self-powered NY2/EC1.5-TES achieved real-time communication between a TES Piano and a computer.