The ammonia detection of cesium lead halide perovskite quantum dots in different halogen ratios at room temperature

Abstract

Recently, all-inorganic perovskite structured nanomaterials CsPbX3 (X = Cl, Br, I or mixed halogen) quantum dots (QDs) have been developed rapidly in many applications such as photovoltaics, light-emitting diodes, and photoelectric detectors due to their excellent optical and photoelectrical properties. Meanwhile, this hot topic material also shows interesting potential in sensing applications because of the sensitive surface and large specific area. The reversible property in gas sensing makes it a promising material to realize highly sensitive visual gas sensor on the fluorescent signal. However, the influencing mechanism of the phenomenon gas molecules is still controversial in many situations. In this paper, we proposed a series of fluorescence turn-on ammonia gas sensors based on spin-coated CsPbX3 film. The wavelength of the fluorescent signal carrier was modulated by altering the ratio of halogen. By properly selecting the proportion of surface ligands and carefully analyzing the experiment results, we believe the dynamic passivation of ammonia molecule on the surface of perovskite QDs made dominated contribution to the sensing mechanism, and the series of CsPbX3 QDs sensor shared a similar trend at room temperature. In addition, the sensors we prepared exhibit impressive performance in sensitivity, response time, and reversibility, showing a good potential for low cost, high precision, miniaturized gas detection based on the optical signal.