Room-Temperature-Grown FAPb0.5Sn0.5I3 Polycrystalline Thick Films for Self-Powered X-Ray Detectors With High Sensitivity and Low Detection Limit.

Abstract

Perovskite polycrystalline thick films are promising for x-ray detection and imaging, yet the simultaneous realization of high sensitivity and a low detection limit remain difficult due to the trade-off between transport and ion migration. Herein, we report the preparation of FAPb0.5Sn0.5I3 (FA = CH(NH2)2) perovskite polycrystalline thick films with negligible Sn2+ oxidation at room temperature by solvent engineering. The as-prepared films deliver exceptional carrier transport properties, as evidenced by an ultralong carrier diffusion length (LD) of 58 µm. Moreover, the high ion migration activation energy (Ea) of 0.67 eV endows the detectors with suppressed dark current and a minimal drift of 2.09 × 10-5 nA cm-1 s-1 V-1. Collectively, these merits result in self-powered x-ray detectors with both high sensitivity of 3.88 × 103 µC Gyair -1 cm-2 and an ultralow detection limit of 0.93 nGyair s-1. Our work may promote the development of stable and low-dose-rate perovskite x-ray imaging.