Self-Powered Acetone Sensing under High Humidity Enabled by a No-Contact Single-Electrode Triboelectric Nanogenerator

In this study, a single-electrode triboelectric nanogenerator (TENG) based on chitosan/SnO2 composite films for self-powered acetone sensing was reported, with particular attention paid to operation under highly humid conditions. The TENG works through periodic contact and separation between a PTFE film and a nylon-encapsulated structure. By introducing SnO2 nanoparticles into the chitosan matrix, the sensing behavior is markedly enhanced. Among the different films investigated, the spray-coated bilayer chitosan/SnO2 film exhibited the best overall performance. Specifically, it delivered a response of 48.7% to 10 ppm acetone at 97.3% relative humidity (RH), which is substantially higher than that of the pure chitosan film (5.1%) and the blended composite film (24.6%). In addition, the s-Chitosan/SnO2-based device showed excellent resistance to humidity interference: its response at 97.3% RH was only 1.2 times higher than that measured at 32.8% RH, outperforming the pure chitosan film, which showed a 2.4-fold increase. The sensing mechanism is attributed to the interaction between acetone molecules and the hydrogen-bond network formed among chitosan, water molecules, and SnO2. Acetone disrupts these hydrogen bonds, leading to changes in surface charge density and, consequently, in the electrical output of the TENG. Overall, this work provides a feasible strategy for developing room-temperature, self-powered acetone sensors with strong humidity tolerance, making them attractive for noninvasive health monitoring applications such as diabetes screening.