Surface-Tension-Controlled Crystallization for High-Quality 2D Perovskite Single Crystals for Ultrahigh Photodetection

The two-dimensional (2D) layered organic-inorganic hybrid perovskites have demonstrated better performance in applications than their 3D counterparts due to their promising stability and excellent optoelectronic properties. In particular, the 2D perovskites show even better performance for certain optoelectronic devices, especially the ones fabricated on (001) plane. Unfortunately, these advantageous characteristics cannot be easily extracted from the randomly oriented microcrystalline films. Herein, we developed a surface-tension-controlled crystallization method to prepare large 2D (C6H5C2H4NH3)2PbI4 ((PEA)2PbI4) perovskite single crystals (PSCs). Using this technique, we have harvested some inch-sized 2D (PEA)2PbI4 PSCs, with the largest one reaching 36 mm in length, resulting in extraordinary device performance. More specifically, the photodetectors fabricated on the (001) plane exhibit responsivity as high as 139.6 A W−1, external quantum efficiency 37,719.6%, detectivity 1.89 × 1015 cm Hz1/2 W−1, and response speed as fast as τrise = 21 μs and τdecay = 37 μs.