Centimeter-sized single crystals of 2D hybrid perovskites toward ultraviolet photodetection with anisotropic photoresponse

Abstract

Two-dimensional (2D) organic–inorganic hybrid perovskites have made remarkable progress in the field of photodetection due to their outstanding semiconducting attributes and solution accessibility. More interestingly, benefiting from the alternating arrangement of organic and inorganic layers, 2D hybrid perovskites are expected to exhibit strong structural anisotropy. However, until now, studies of anisotropy for 2D hybrid perovskites toward photodetection, especially toward ultraviolet (UV) photodetection, remain highly desirable. Here, we successfully obtain centimeter-sized single crystals of the 2D hybrid perovskite (BA)₂CsPb₂Br₇ (1, BA = n-butylammonium) and provide a demonstration of sensitive UV photodetection with anisotropic photoresponse. Grown via a temperature-cooling solution method, single crystals of 1 feature high crystalline qualities with a low trap density of 2.28 × 10¹⁰ cm⁻³. Notably, photodetectors using such high-quality crystals exhibit an excellent photoresponse to UV illumination with a large photoelectric anisotropy ratio of up to ∼25. Such a high anisotropy ratio exceeds many other 2D hybrid perovskites and can be ascribed to the anisotropic carrier transport within 1. Moreover, a considerable on/off ratio of ∼10³ and a highly sensitive detectivity of up to ∼10¹¹ Jones are also achieved. This research may pave the way for further applications of large-sized 2D perovskite single crystals for anisotropic photodetection.