Study on a Mixed-Cation Halide Perovskite-Based Deep-Ultraviolet Photodetector

Deep-ultraviolet (UV) sensing has attracted significant interest because of its wide range of applications. A mixed-cation halide perovskite-based photodetector prepared by mixing CH3NH3PbX3 (X = I, Br, and Cl) and HC(NH2)PbX3 (X = I, Br, and Cl) exhibits high stability and excellent light absorption. In this study, perovskite was prepared by mixing CH3NH3+ (FA+) and HC(NH2)2+ (MA+) cations using I−, Br−, and Cl− halide anions. The bandgaps of the prepared perovskites increased to 1.48, 2.25, and 2.90 eV with I-, Br-, and Cl-, respectively, and the light absorption spectra shifted to shorter wavelengths. An increase in the redshift of the light absorption led to an increase in the photocurrent. The FAPbCl3-MAPbCl3-based photodetector showed a high responsivity of 5.64 mA/W, a detectivity of 4.03 × 1011, and an external quantum efficiency of 27.3%. The results suggested that the FAPbCl3-MAPbCl3 perovskite is suitable for deep-UV light sensing and is an excellent candidate for the fabrication of a sensitive photodetector.