Controllable Cs _xFA_{1- x}PbI₃ Single-Crystal Morphology via Rationally Regulating the Diffusion and Collision of...

Cs _xFA_{1- x}PbI₃ single crystals are expected to provide more excitement in optoelectronic applications, including photodetector, laser, light-emitting diode, etc. Herein, we aim to gain an in-depth understanding of the growth mechanisms of perovskite single crystal with various morphologies in view of microscopic dynamics by the combination of component, structure, and solvent engineering. A sequence of Cs _xFA_{1- x}PbI₃ (0 ≤ x ≤ 0.14) perovskite single crystals with a dodecahedron morphology and tunable aspect ratio can be obtained by means of a solution-processed uniform-cooling approach. The optimized Cs_0.1FA_0.9PbI₃ single crystals prepared in γ-butyrolactone mixed with dimethyl sulfoxide are theoretically and experimentally demonstrated to have superior performances, e.g., extremely higher long-term stability, lower trap density, and higher mobility. The broadband absorption, i.e., 300-910 nm, enables its application in near-infrared detection (880 nm), and the corresponding detector demonstrates higher responsivity at different light intensities and a fast photocurrent response (τ₁ = 11 μs, τ₂ = 10 μs). Equally important, we also explore the application of optimized Cs_0.1FA_0.9PbI₃ single crystals with a tunable aspect ratio in an X-ray detector and the extremely high sensitivity (2772.1 μC Gy_air^-1 cm^-2 under a bias of 150 V) demonstrates their good potential for radiation detection.