Superior room temperature ammonia gas sensing of copper selenide nanoflowers

Abstract

Facile wet chemical synthesis was utilized to synthesize nanoflowers of copper selenide (CuSe) that exhibited exceptional room temperature ammonia (NH3) gas sensing capability. Observations of surface morphology revealed the presence of petal-like structures arranged in a flower-like pattern. The layered materials have been analyzed for their crystalline structure, phase, composition, and band gap by utilizing X-ray diffraction, Transmission Electron Microscopy, Raman spectroscopy, and energy-dispersive X-ray spectroscopy, UV-Vis, respectively. At ambient conditions, CuSe nanoflowers-based sensor demonstrated exceptional sensitivity, reaching up to 79% (200 ppm NH3) with short response and recovery time of 12.9 s and 6.3 s, respectively, at 5 ppm gas concentration. The sensor exhibited rapid response and recovery times, a broad concentration range, long-term stability over extended periods, exceptional specificity towards NH3, and good repeatability owing to its distinct flower-shaped structures assembled in thin layers. Density Functional Theory simulations were conducted to investigate the interactions between NH3 and CuSe. Our findings revealed an increase in the adsorption energy of NH3 on CuSe, indicating a stronger binding affinity. We observed a higher charge transfer from CuSe to NH3, which suggests an increase in conductivity. This increase in conductivity enhances the superior sensing capability observed in the experimental results.