Room‐Temperature Solvent Evaporation Induced Crystallization: A General Strategy for Growth of Halide Perovskite Single Crystals by Applying the Le Chatelier's Principle

Abstract The growth of high‐quality halide perovskite single crystals is imperative to study their intrinsic physical properties and to realize high‐performance optoelectronic devices. Here, a room‐temperature solvent evaporation‐induced crystallization (RTSEIC) method is reported based on Le Chatelier's principle, which provides a general strategy to grow halide perovskite single crystals including 3D, 2D, 1D, and 0D, and either hybrid or all‐inorganic halide perovskites. Taking 2D n‐BA₂PbBr₄ (n‐BA = butylammonium) as an example, the room‐temperature crystallization kinetics is demonstrated. The centimeter‐sized n‐BA₂PbBr₄ single crystals exhibit an extremely small full width at half maximum (FWHM) of 0.024° in (0 0 2) plane rocking curve and a small trap density of 2.74 × 10¹⁰ cm⁻³. The superior crystalline quality endows the n‐BA₂PbBr₄ single crystal ultraviolet photodetectors with recorded performance among reported n‐BA₂PbBr₄ ultraviolet photodetectors, demonstrating a detectivity reaching 1.8 × 10¹³ Jones, a fast response time of 55 µs and a high on‐off ratio of 10⁴. The low‐cost, simple, general, and efficient RTSEIC method is anticipated to promote the blossoming of halide perovskites single crystals.