Enhanced On–Off Ratio for Ni(OH)₂·0.75H₂O-MAPbBr₃-Based Photodetectors

Organic–inorganic perovskite materials with high absorption coefficients and high carrier mobility have been studied for active material photodetector applications. However, noise generated by high dark current and the poor stability caused by the migration of perovskite ions have been the main problems limiting their further applications. In this paper, we first synthesized Ni(OH) 2 ·0.75H 2 O-MAPbBr 3 thin films in situ by introducing nickel acetate and demonstrated by X-ray crystallography (XRD) that the crystalline structures in the films can be tuned by modulating the change of component ratio in perovskite and Ni(Ac) 2 . Then again based on this, we fabricated simple photodetectors using this film as a light-absorbing layer. As a result, pure MAPbBr 3 -based photodetector has an ON/OFF ratio of only 6.19, while the amount of nickel acetate we fabricated is up to 131.20. Moreover, the Ni(OH) 2 ·0.75H 2 O-MAPbBr 3 -based photodetector exhibits excellent stability and can maintain 94.6% of the original performance after 600 cycles, as well as retain 84% of its original performance after 60 days under ambient conditions.