Growth and NO2 sensing properties of Cs2SnI6 thin film

In this study, Cs2SnI6 thin film was synthesized on a glass substrate through a two-step process using the chemical vapor deposition (CVD) method and was subsequently used as a NO2 gas sensor. First, the CsI spheres with an average diameter of 360 nm were fabricated on the glass substrate using a CVD system at 240 °C. Second, Cs2SnI6 film was formed through the reaction of CsI spheres with SnI4 vapor at 200 °C for 1 h. Finally, the as-synthesized Cs2SnI6 thin film based gas sensor was then fabricated to explore its potential applications. The results indicated that the device showed good selectivity, stability, and detection for NO2 with low concentration at room temperature. In addition, the effect of humidity on NO2-sensing performance of the device was further studied. Furthermore, the NO2 sensing mechanism of the Cs2SnI6 thin film was discussed. Hence, this study helps understand the gas sensing mechanism of halide perovskite Cs2SnI6 and the room temperature development of NO2 gas sensors.