Effect of heterogenous dopant and high temperature pulse excitation on ozone sensing behavior of InO nanostructures and an image recognition method coupled to ozone sensing array.

Ground-level ozone (O) is a primary air pollutant with potential adverse impacts on human health and ecosystems. Aiming to detect O concentration and develop efficient O sensing materials, sensing behavior of heterogenous cation (Fe, Sn and Sb) doped InO nanostructures was investigated. The incorporation of these cations modulated the electronic structure of semiconductor oxides, affecting the density of chemisorbed oxygen species and reactive sites. From O sensing results, Fe doped InO based sensors featuring saturated resistance curves in O gas, demonstrated fast sensing speed and qualified detection threshold (20 ppb). In contrast, Sn and Sb doped counterparts exhibited non-saturated sensing curves, resulting in slower response/recovery speed. As a proof-of-concept, these optimized sensors were integrated as the sensor array. Coupled to the image recognition technique, this sensor array could successfully discriminate O and NO. That is, through the tailored combination of material modulation and sensor array, this study paves a novel approach for highly sensitive and selective O detection.