Dense Stacking of Millimeter-Sized Perovskite Single Crystals for Sensitive and Low-Bias Hard X-Ray Detection

Metal halide perovskite single crystals are promising for hard X-ray detection, but growth of large-sized thin single crystals and inhibition of halide ion migration under high bias are challenging. Herein, the preparation of dense stacking of oriented millimeter-sized perovskite single crystals with capability of large-area fabrication, controlled thickness, and high ion migration activation energy ( E a)is reported. The oriented growth results in absence of grain boundaries parallel with the substrates, leading to large carrier mobility-lifetime ( µτ ) product of 2.7 × 10 −3 cm 2 V −1 , which is comparable to values of many perovskite bulk single crystals. Under low bias, hard X-ray detectors exhibit high sensitivity of 1.2 × 10 4 µC Gy −1 cm −2 and low detection limit of 87.5 nGy s −1 , which are comparable to those of many single-crystal hard X-ray detectors under high bias. Moreover, combination of low bias and high E a results in weak halide ion migration and small dark current drift of 3.2 × 10 −4 nA cm −1 s −1 v −1 . Benefited from the superior detector performance, high-contrast hard X-ray imaging can be obtained at a low dose rate of 1.26 µGy s −1 . The work may promote the application of perovskite hard X-ray detectors in practical imaging area.