SnSe Nanoflakes for a NO₂ Sensor at Room Temperature

Tin selenide (SnSe) is gaining significant interest in the scientific research community by virtue of its fascinating electrical, chemical, and physical characteristics. Surprisingly, the incorporation of SnSe in the area of gas sensors has been very little explored. Due to its distinctive properties, SnSe can be utilized as an effective material to detect nitric oxide (NO2) at ambient temperature. In this paper, we report the optimized synthesis of SnSe nanostructures through a low-cost hydrothermal method and their employment as a sensing material for NO2 detection (400 ppb to 1 ppm). Different structures (nanoparticles, nanoflakes, and nanoflowers) were obtained depending upon varied growth times (12, 16, and 20 h). An extensive material characterization study was performed, evidencing the formation of the desired structure and morphology of SnSe. The optimum sensor (S_16) exhibited a response of 12.11 in the presence of 1 ppm of NO2 at room temperature (25 °C) along with promising reversibility. The theoretical limit of detection was found to be 116 ppb. The sensor offered excellent sensitivity and selectivity due to its high interactive tendency with NO2 molecules. The demonstrated work paves the way for an adequate alternative utilizing SnSe as a sensing material for room-temperature-operated selective gas sensors.