Polarization-Dependent Optoelectronic Performances in Hybrid Halide Perovskite MAPbX3 (X = Br, Cl) Single-Crystal Photodetectors.

Hybrid organic-inorganic lead halide perovskites (HOIPs) have received significant attention because of their impressive performances in the fields of solar cells and photoelectric detection. In the past five years, great efforts have been made to improve the crystallinity, reduce grain boundaries, and enhance the stabilities of perovskite films. Compared with films, HOIP single crystals possess fewer grain boundaries and stronger optoelectronic properties and can be applied in optoelectronic devices. As the most popular HOIP member, single crystals of MAPbX3 (X = Br, Cl) are deemed as important candidates for ultraviolet-visible photodetectors, in which the crystal structure anisotropy largely affects the detection performance. In this study, high-quality cubic single crystals of MAPbBr3 and MAPbCl3 were successfully grown from solutions. Taking advantages of their smooth (100) facets, planar metal-semiconductor-metal photodetectors were fabricated using Au interdigitated electrodes. The optoelectronic performances under nonpolarized and linearly polarized lights were explored. The optoelectronic performances were dependent on linearly polarized lights. Interestingly, both responsivity and external quantum efficiency were greatly enhanced under the excitation with linearly polarized lights. Moreover, the polarization-related optical absorptions and the electron densities within the (100) plane could be used to interpret different optoelectronic performances of single crystals of MAPbX3 (X = Br, Cl) under various linearly polarized lights.