Lattice engineering for stabilized black FAPbI perovskite single crystals for high-resolution x-ray imaging at the lowest dose.

Preliminary theoretical analyses indicate that lattice relaxation may be used to release lattice strain in the FAPbI perovskite to warrant both high x-ray detection performance and improved stability. Herein, we demonstrate stable black α-phase FAPbI single crystals (SCs) realized by lattice engineering via annealing in the ambient atmosphere. The engineered α-FAPbI SC detector shows almost all the best figures of merit including a high sensitivity of 4.15 × 10 μC Gy cm, a low detection limit of 1.1 nGy s, a high resolution of 15.9 lp mm, and a short response time of 214 μs. We further demonstrate high-definition x-ray imaging at a dose rate below 10 nGy s on the FAPbI SC, indicating a minimal dose-area product of 0.048 mGy cm to the patient for one-time posteroanterior chest diagnosis, which is more than 3000 times lower than the international reference level of 150 mGy cm. In addition, the robust long-term stability enables the FAPbI SC x-ray detector to work steadily for more than 40 years.