The Sensing Selectivity of Gas Sensors Based on Different Sn-Doped Indium Oxide Films

The gas-sensitive performance and selectivity of gas sensors via different Sn-doped indium oxide (In2O3) films have been investigated. The response characteristics were significantly enhanced to methanol (CH4O), ethanol (C2H6O), and acetone (C3H6O) with the increase in Sn content, while the response time and the recovery time became shorter. The sensor exhibited the strongest response to ethanol, followed by acetone and then methanol with all the ratios of In2O3 (90%, 85%, and 80%) and SnO2 (10%, 15%, and 20%). The mechanism of Sn doping on the gas sensing selectivity was calculated using the density functional theory (DFT) method, which perfectly explained the experimental results. The sensors demonstrated high selectivity towards ethanol, even in the presence of interfering gases. In addition, the sensors showed effective detection of the target gas with 10 ppb and demonstrated good repeatability. This work systematically analyzed the priority selectivity of In2O3-based gas sensors, providing a new path for gas detection in multi-interference and complex environments.