High-Performance Planar-Type Ultraviolet Photodetector Based on High-Quality CH3NH3PbCl3 Perovskite Single Crystals.

A hybrid perovskite MAPbCl3 (MA = CH3NH3+) single crystal is considered to be one of the most viable candidates for the development of photodetectors because of its outstanding optoelectronic properties. However, the relatively lower crystalline quality of the reported MAPbCl3 single crystals fabricated by the traditional one-step inverse temperature crystallization results in momentous degradation in the performance of their photodetectors. Here, we present a novel two-step temperature process to fabricate high-quality MAPbCl3 single crystals, namely, lower temperature nucleation and higher temperature crystallization. These MAPbCl3 single crystals present low defect density (∼7.9 × 109 cm-3) commensurate with the best-quality crystals of hybrid organic-inorganic lead halide perovskites reported so far. Moreover, a high-performance ultraviolet photodetector was demonstrated on MAPbCl3 single crystals. At 30 V, the peak responsivity at 415 nm of the photodetector is as high as 3.73 A W-1 (light intensity = 1 mW cm-2), ∼2-3 orders of magnitude higher than that of the previously reported MAPbCl3 photodetectors. Meanwhile, the device has an ultrafast response speed with a rise time of 130 ns, which is one of the shortest values of MAPbX3-based photodetectors. Our findings open a new way to obtain high-quality perovskite single crystals and their high-performance photodetectors.