Effect of heterogenous dopant and high temperature pulse excitation on ozone sensing behavior of In2O3 nanostructures and an image recognition method coupled to ozone sensing array

Ground-level ozone (O 3 ) is a primary air pollutant with potential adverse impacts on human health and ecosystems. Aiming to detect O 3 concentration and develop efficient O 3 sensing materials, sensing behavior of heterogenous cation (Fe 3+ , Sn 4+ and Sb 5+ ) doped In 2 O 3 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 3 sensing results, Fe 3+ doped In 2 O 3 based sensors featuring saturated resistance curves in O 3 gas, demonstrated fast sensing speed and qualified detection threshold (20 ppb). In contrast, Sn 4+ and Sb 5+ 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 3 and NO x . That is, through the tailored combination of material modulation and sensor array, this study paves a novel approach for highly sensitive and selective O 3 detection.