Reducing Energy Loss of 2D Perovskite Single Crystal for Stable and Efficient X-Ray Detection by Quenching the...

Two-dimensional (2D) halide perovskites are demonstrated as promising materials for X-ray detection because of their large resistivity, excellent stability, tunability of interlayer spacing, and strong X-ray absorption. However, the high exciton binding energy of 2D perovskites usually generates obvious radioluminescence (RL) under X-rays, which causes non-negligible energy loss during detection. In this work, the RL intensity is successfully reduced and the carrier recombination lifetime is extended through rational design of ion (Bi³⁺) substitution to greatly improve the X-ray detection performance of the 2D perovskite single crystals (SCs). Specifically, the quenched RL reduces energy loss, and the extended RL lifetime improves the carrier collection efficiency during X-ray detection. In addition, 2D SCs with Bi incorporation exhibit higher ion migration activation energy and shorter interlayer spacing than the pristine SCs, thus realizing lower current drift and higher carrier mobility-lifetime (µτ) product. Therefore, the 2D SC detectors achieve high detection sensitivity of 5217.3 µC Gy^-1 cm^-2, low detection limit of 2.5 nGy s^-1 and excellent response stability. The rare combination of these excellent properties enables the detectors to achieve high-resolution X-ray imaging. This work provides a new design idea and a specific manipulation strategy for further improving the X-ray detection performance of 2D SCs.