Improving sensitivity of self-powered room temperature NO2 sensor by triboelectric-photoelectric coupling effect

Nitrogen dioxide sensors with high sensitivity and low energy consumption are demanded for atmosphere sensing networks. Here, a self-powered room temperature NO2 sensor has been developed based on the conjugation between the triboelectric and photoelectric effect. By converting the mechanical motions into electricity, a triboelectric nanogenerator (TENG) serves as a power source to simultaneously drive chemoresistive gas sensing and UV illumination. Under a 5Hz external impact, the output voltage drop across interdigital electrodes has a proportional relationship with the NO2 concentration. A self-powered optomechatronic gas sensor (OGS) with hydrothermal ZnO nanowires synthesized at a concentration of 0.035mol/l exhibits a superior response (similar to 14.8) and sensitivity (0.302ppm(-1)) than those synthesized at other concentrations. Furthermore, the influence of the external force frequency and rectification on the gas sensing properties was systematically investigated. It is found that the TENG induced built-in electric field can effectively modulate the internal quantum efficiency and thus the sensing performance of OGSs. This work not only paves the way for constructing self-powered optomechatronic devices and systems but also pushes forward the active multifunctional network node for environmental monitoring.