High-quality, Pb-free, pinhole-reduced MA0.7FA0.3SnBr3 perovskite photodetector via incorporating graphite

•We first report a strategy for obtaining solution-processed, pinhole-free, high-quality MA0.7FA0.3SnBr3 perovskite films by simple solution process with the incorporation of graphite.•Through incorporating graphite, the surface topography of the perovskite film was improved and the pin-holes existed in the film was reduced greatly.•Compared with the spin-coated MA0.7FA0.3SnBr3 PD without the graphite, the metal-semiconductor-metal PDs with the graphite show a higher photocurrent, a bigger detectivity with the value of 6.7 × 1010 Jones. [Display omitted] Non-toxic divalent tin has been reported to be the most potential substitute for lead in organic and inorganic halide perovskites and the Sn-based perovskite materials attract tremendous attention in the photoelectric field. However, the Sn-based perovskite films fabricated by using the solution process with spin-coating technology often behave poor quality with many pinholes, hindering the device performance. Herein, we introduce a strategy for obtaining high-quality MA0.7FA0.3SnBr3 perovskite films by simple solution process with the incorporation of graphite in the perovskite precursor solution. Through incorporating graphite, the surface topography of the perovskite film was improved and the pin-holes existed in the film was reduced greatly. Besides, with the increase of the graphite dose in the precursor the dark current is reduced gradually, and the photocurrent shows a trend that increases first and then decreases, resulting in the optimal dose of about 0.5 mg. Furthermore, we achieved high-performance Sn-based perovskite photodetectors (PDs) with the detectivity of 6.7 × 1010 Jones, and the rise/fall time of 45/420 ms. These results demonstrated good practical application for the Sn-based perovskite PDs.