Oxygen-Vacancy-Rich In2O3 for Highly Sensitive and Low-Limit Ozone Detection at ppb Levels

Developing an ozone (O3) sensor with high sensitivity and low detection limits under variable humidity conditions remains a longstanding challenge. Here, we report an oxygen-vacancy-rich In2O3 (Va-In2O3) sensor fabricated via vacuum annealing combined with a temperature-modulation strategy. These oxygen vacancies not only provide a large number of active sites for O3 adsorption but also decrease the band gap and increase the carrier concentration, thereby enhancing the electron mobility. As a result, the Va-In2O3 sensor can detect O3 at a lower limit of 10 ppb under 3% RH, and its response is 12.6 times that of In2O3. Meanwhile, it still maintains high sensitivity even at 73% RH, and the response to 30 ppb O3 is 63.7. Furthermore, the temperature modulation strategy enables decoupling of the sensing and recovery processes, achieving high response at low temperature and rapid recovery at elevated temperature. Additionally, the temperature modulation strategy optimally matches the response process with the recovery process, achieving rapid recovery (<5 s) under high response conditions. This work provides an effective oxygen vacancy regulation strategy for achieving high-performance O3 detection under actual conditions.