Improved photoelectric and thermal stability in all-inorganic metal halide perovskite by mixed-halogen

Halide perovskite (ABX3) has become an exciting material for research in next-generation optoelectronic devices because of their remarkable photoelectric properties of high stability, high luminescent quantum yield and high carrier mobility. However, the presence of different halogen elements in perovskite could have a significant impact on their optical physical properties. That's because they have a huge differences in the environmental exchange and migration characteristics. In this work, the samples with three different anions of CsPbBr₃, CsPbCl₃, and CsPb(Br_0.5Cl_0.5)₃ were used, and the electrical stability and photostability experiments were carried out under the dark environment and under continuous illumination with a 532 nm wavelength light, respectively. The electrical, optical and thermal stability of the photodetectors were analyzed by adding a constant voltage of 10 V to the photodetectors and repeating the experiments for 10 times in the dark and under continuous illumination, and the trends of the I-V curves of the photodetectors were recorded. The experimental results show that the anionic halides have considerable defects leading to their poor electrical, optical and thermal stability under dark and continuous light conditions. However, the all-inorganic mixed halide perovskite CsPb(Br_0.5Cl_0.5)₃ is able to form tightly bound surface ligands effectively suppressing the defects generated on the surface, which results in its better stability and linearity. Therefore, it indicates that the photodetectors based on allinorganic mixed halide perovskite have excellent stability, which provides a promising way to promote the research of all-inorganic halide perovskite devices in the future.