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 (Ea)is reported. The oriented growth results in absence of grain boundaries parallel with the substrates, leading to large carrier mobility-lifetime (mu tau) product of 2.7 x 10-3 cm2 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 x 104 mu C 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 Ea results in weak halide ion migration and small dark current drift of 3.2 x 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 mu Gy s-1. The work may promote the application of perovskite hard X-ray detectors in practical imaging area. Dense stacking of oriented millimeter-sized perovskite single crystals with the capability of large-area fabrication, controlled thickness, high ion migration activation energy, and large carrier mobility products are in situ grown on ITO substrate. 120 kV hard X-ray detectors working under low bias exhibit high sensitivity, low detection limit, and small dark current drift. image