Novel chitosan/ZnO bilayer film with enhanced humidity-tolerant property: Endowing triboelectric nanogenerator with acetone analysis capability

Endowing triboelectric nanogenerator (TENG) with excellent acetone-sensing and humidity-tolerant property is an effective strategy for prospective breath diagnosis of diabetes without additional power supplies. In this work, a TENG based on chitosan (CTS)/zinc oxide (ZnO) bilayer film, that acted both as sensing layer and triboelectric layer, was successfully developed for room-temperature acetone detection with enhanced humidity-tolerant property. The as-fabricated CTS/ZnO based triboelectric acetone sensor (CTS/ZnO-TAS) exhibited higher sensitivity (1.9545%/ppm), superior response (19.02% under 10 ppm of acetone) and lower detection limit (1 ppm) than the CTS-TAS under 89.3%RH. Meanwhile, the better humidity-tolerant property of CTS/ZnO-TAS was attributed to the formation of abundant hydrogen bonds between CTS and ZnO, which could occupy massive hydrophilic functional groups of the sensing materials, resulting in the decrease of active water adsorption sites. Finally, a sensing mechanism coupled triboelectric effect with gas sensing principle was established to interpret the enhanced acetone-sensing performance of the CTS/ZnO-TAS. This work proposes a CTS/ZnO-based TENG with enhanced humidity-tolerant property towards acetone sensing, demonstrating a potential application in noninvasive diabetes diagnosis.