Suppressed ion migration for high-performance X-ray detectors based on atmosphere-controlled EFG-grown perovskite 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 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. The researchers improve the properties of halide perovskite for high-performance X-ray detection by edge-defined film-fed crystal growth. In particular, high resistivity, low trap density, suppressed ion migration and reduced leakage current are demonstrated. They enable detectors with an extremely low detection limit and high sensitivity.