Solution-Processed Epitaxial Growth of MAPbI3 Single-Crystal Films for Highly Stable Photodetectors

Recent years, organic-inorganic hybrid perovskites (OIHPs) have been widely used in applications, such as solar cells, lasers, light-emission diodes, and photodetectors due to their outstanding optoelectronic properties. Nowadays photodetectors based on perovskite films (PFs) suffer from surface and interface traps, which result from low crystalline quality of perovskite films and lattice mismatch between perovskite films and substrates. Herein, we fabricate MAPbI 3 -(MA = CH 3 NH 3 ) single-crystal films (SCFs) on MAPbBr 3 single crystal substrates in MAPbI 3 precursor solution during crystallization process via solution-processed epitaxy. Benefit from the good lattice matching, epitaxial MAPbI 3 SCFs with high crystallinity and smooth morphology are of comparable quality to MAPbI 3 PSCs and are of better quality than MAPbI 3 polycrystalline films. Here we report that epitaxial MAPbI 3 SCFs have a low trap density of 5.64×10 11 cm –3 and a long carrier lifetime of 11.86 μs. In this work, photodetector based on epitaxial MAPbI 3 single-crystal film (SCF) exhibits an excellent stability of a long-term stable response after 120 days, a fast response time of 2.21 μs, a high responsivity of 1.2 A W –1 and a high detectivity of 3.07 ×10 12 jones.