One step method of ions regulation and defect passivation of perovskite film for high performance photodetector

A new class of semiconducting materials called organic-inorganic halide perovskites hereafter could lead to commercial photoelectric devices due to the ultrahigh-performance and cost effect. However, further improvement of detector performance is hindered by the intrinsic problems in thin film systems, these problems become one of the biggest obstacles for perovskite materials toward commercial viability. To improve the quality of perovskite film, there are two types of methods which are usually used including chemical modification and physical processing methods. But in general, the traditional physical processing method cannot adjust the ion composition when fabricating perovskite film. Herein, we propose a simple and one step brush-coating method to simultaneously adjust the ion composition and morphology perovskite film. On the basis of selective adhesion of brush material for different ions e.g., I− and Br− in the precursor solution, the excess PbI2 in the perovskite film could be achieved to passivate the defects in the crystal boundaries, leading to the effectively suppressed dark current down to 10−12 A. Meanwhile, brush-coating process promotes highly crystalline structures and fewer grain boundaries of perovskite film. The brush-coating based photodetector shows an excellent detectivity of ∼1012 Jones at the bias of −0.5 V. The results suggest a promising strategy for ion components and film morphology of perovskite layer for outstanding perovskite-based photodetector and compatibility with large-area fabrication.