Inhibition of buried cavities and defects in metal halide perovskite photodetectors via a two-step spin-coating method. Issue 20 (12th May 2022) - Wang, Silei
Abstract : The responsivity of perovskite photodetectors is improved by modified two-step spin-coating method, and the lift-off technique reveals that the performance improvement is related to the reduced crystal imperfections and nanocavities at the buried perovskite interface. Abstract : The performance of perovskite photodetectors (PPDs) is sensitive to the quality of their perovskite films. Solution-processed perovskite films suffer from excess lead halide and irregular nanocavities located at the buried interface, which result in a high dark current density and hinder the improvement of the PPD performance. Herein, we could govern the perovskite growth by introducing the modulating MAI molecule in the PbI2 precursor in a modified two-step spin-coating method. Consequently, we obtained a high-quality (large grain size, pinhole-free and well-packed) perovskite layer with uniform thickness. Also, we fabricated a photodiode-type PPD with a p–i–n configuration. At a reverse bias of −1.5 V, the optimum PPD achieved a high specific detectivity of up to 5 × 10 11 Jones and a decent responsivity of 0.79 A W −1 under 532 nm laser irradiation with a light intensity of 1 μW cm −2 . Meanwhile, it exhibited a fast response of 2.6 μs and 72.8 μs for the rise and fall times, respectively. This strategy enriches the approaches for preparing high-quality perovskite films for diverse perovskite optoelectronic devices.