SnSe nanosheet arrays film for trace NO2 detection at room temperature

The development of high-performance room temperature sensors for detecting trace nitrogen dioxide (NO2) levels is critical for Internet of Things based environmental monitoring. We present a novel NO2 gas sensor based on tin selenide (SnSe) nanosheet arrays films deposited on a variety of substrates using vacuum thermal evaporation. The nanosheets formed well-oriented arrays and had a thickness of about 10 nm and lateral size of 0.2–1 µm. The films’ synthesis was well controlled, and the NO2 gas sensors’ performance was tuned by adjusting the microstructure of the films. The gas sensors were highly responsive to NO2 concentrations ranging from 100 to 300 ppb, it can achieve a response of 155% towards 300 ppb concentration of NO2 at room temperature; the gas sensing performance is affected by film thickness and microstructure. At a high NO2 gas concentration of 10 ppm, a response time of 12 s and response rate of 700% were achieved at room temperature. Furthermore, the high selectivity and repeatability of the SnSe nanosheet arrays film gas sensor were demonstrated. Because of its ease of fabrication and high performance, the NO2 gas sensor described here has promising applications.