Anisotropic Optoelectronic Properties of Melt-Grown Bulk CsPbBr₃ Single Crystal

All-inorganic perovskite CsPbBr₃ has been considered as one of the star semiconductors due to its inspiring optoelectronic properties and higher stability than the organic-inorganic hybrid counterparts. The preparation of large-size single crystals with low trap density and the performance optimization on the devices still challenge the commercial application of this material. Here the large transparent CsPbBr₃ single crystal (ϕ 24 mm × 90 mm) was grown by a modified Bridgman method. With the determination of crystallographic directions, the anisotropic optoelectronic properties were investigated for the first time. The result shows a high electron mobility (11.61 cm²/(V s)) along the b axis, one order of magnitude higher than that along the c axis. Moreover, the photoresponse measurement yields a high responsivity (5.83 A/W) and external quantum efficiency (1360%) on the (001) plane irradiated by the 532 nm laser diode with 1 mW/cm² under 10 V bias, which is a 305% enhancement compared with the (010) plane. Our study on anisotropic optoelectronic properties of CsPbBr₃ will provide a significant approach to enhance the performance of single-crystalline devices.