Suppressed ion migration for high-performance X-ray detectors based on atmosphere-controlled EFG-grown perovskite CsPbBr3 single crystals
摘要
Halide perovskites have shown great potential for X-ray detection in medical imaging and product inspection applications. However, the ion migration in perovskites causes large noise and baseline drift, deteriorating the X-ray detection and imaging performance. Here 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. Compared with the vertical Bridgman (VB)-CsPbBr3 SCs, the EFG-CsPbBr3 SCs show a much lower trap density, a higher resistivity (1.61 × 1010 Ω cm) and a larger ion migration activation energy (0.378 eV), decreasing the leakage current and baseline drift. An X-ray detector based on EFG-CsPbBr3 SCs hence exhibits outstanding balanced performance, with a negligible dark-current drift of 1.68 × 10−9 μA cm−1 s−1 V−1, an incredibly low detection limit of 10.81 nGyair s−1 and a sensitivity of 46,180 μC Gyair−1 cm−2 under a high electric field of 5,000 V cm−1. Furthermore, the detector maintains a stable response for 30 days. Our work provides an effective strategy to improve lead-halide perovskite SCs for high-performance X-ray detection and imaging.