Minute‐Scale Rapid Crystallization of a Highly Dichroic 2D Hybrid Perovskite Crystal toward Efficient Polarization‐Sensitive Photodetector

Abstract 2D hybrid perovskites demonstrate better performances than 3D counterparts in certain optoelectronic devices, whereas their natural attributes cannot be extracted from microcrystalline films, such as the natural dichroism for polarized light detection. Herein, for the first time, unusual minute‐scale rapid crystallization is developed to grow bulk crystals of 2D hybrid perovskite, (FPEA)₂PbI₄ (1, FPEA is p‐fluorophenethylammonium), which enables superior carrier transport property (≈64.1 ns) and low trap density (≈10¹⁰ cm⁻³). The rapid growth rate of 27.3 mm³ h⁻¹ is almost two orders of magnitude higher than for other 2D counterparts. Strikingly, its natural quantum‐confined motif results in extraordinary dichroism with optical absorption ratio α_c/α_a ≈ 2.05, revealing great promises for polarized light detection. Consequently, crystal‐based photodetectors exhibit large photocurrent dichroic ratio I_max/I_min ≈ 2.1, fast response time (400 µs), and high detectivity (10¹¹ Jones) to the polarized light. This is the record‐fast crystallization of highly dichroic 2D hybrid perovskites, which opens a new prospect for their future optoelectronic device applications.