Suppressed Ion Migration for High-performance X-ray Detectors Based on Atmosphere-Controlled EFG-Grown CsPbBr3 Single Crystals

Abstract

Halide perovskites have shown great potential for X-ray detection in medical imaging and product inspection applications. However, the ion migration in lead halide perovskites, which is usually affected by crystal defects, causes large noise and baseline drift, deteriorating the X-ray detection and imaging performance. In this work, we adopt the atmosphere-controlled edge-defined film-fed growth (EFG) method to grow high-quality shape-controlled CsPbBr3 single crystals (SCs) in an Ar and HBr mixed atmosphere for the first time. Compared with the vertical Bridgman (VB)-CsPbBr3 SCs, the EFG-CsPbBr3 SCs show a much lower trap density (4.24 × 108 cm− 3), a higher resistivity (1.61 × 1010 Ω cm), and a larger ion migration activation energy (202.07 meV), decreasing the leakage current and baseline drift. The X-ray detector based on the EFG-CsPbBr3 SCs hence exhibits outstanding balanced performance, with a negligible dark current drift of 1.68 × 10− 9µA cm− 1 s− 1 V− 1, an incredibly low detection limit of 10.81 nGyair s− 1, and a sensitivity of 46180 µC Gyair−1 cm− 2 under a high electric field of 5000 V cm− 1. Furthermore, the detector maintains a stable response for 30 days and exhibits X-ray images for 70 and 120 keV irradiation. Our work provides an effective strategy to improve lead halide perovskite SCs for high-contrast X-ray detection and imaging.