Fabrication of Photodiodes Based on Solution-Processed Perovskite Single Crystals

Solution-processed organic-inorganic perovskites MAPbX
₃
(MA = CH
₃
NH
₃
and X = Cl, Br, and I) have been emerged as potential material for photodetection. Especially photodiodes based on perovskites have shown low dark current and high gain. However, intrinsic perovskites require functional layers to establish photodiodes and these functional layers' small charges mobility and high traps density make photodiodes based on perovskites low response speed. Here, we directly grow homojunctions based on perovskite single crystals (PSCs) during the crystallization process. The pristine PSCs act as p-type donor and epitaxial growth layer with Se doping act as n-type acceptor. With simple structure Au- homojunctions- Au, our photodiodes could work under a large reverse voltage bias range from 0 to 200 V with low noise and result wide dynamic range and high response speed. Using applied voltage to control the width of depletion layer, we achieve enhanced photodetection in near-band photo detection. Our work provides useful information in solution-processed devices design.