Illumination-Dependent Photoelectric Anisotropy in Cs_3Bi_2I_9 Single Crystal Sheets

摘要

Lead-free all-inorganic perovskite single crystals are being pursued intensivelybecause of their reduced biological toxicity and enhanced material stability,greatly relieving two major bottlenecks of practical device applications.However, the investigation of their predicted photoelectric anisotropy is stillabsent, especially under visible and near-infrared light illuminations. In thiswork, the high-anisotropic photodetectors are reported based on Cs_3Bi_2I_9single crystal sheets. The photoelectric performances are superior along thehigh-conductance cleavage plane (001), exhibiting over two-order magnitudeanisotropy in contrast with that along the high-resistance cross-plane.Particularly, these anisotropies are varied with illumination wavelengthsof different penetration depths. Moreover, the anisotropy is also evidentlyinfluenced by illuminate positions due to the lateral self-driven effects. Thiswork enriches anisotropic photoelectric exploration in lead-free all-inorganicperovskite materials and may motivate new strategies to achieve performance-improved in-plane photodetectors.