Lattice engineering for stabilized black FAPbI 3 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 3 perovskite to warrant both high x-ray detection performance and improved stability. Herein, we demonstrate stable black α-phase FAPbI 3 single crystals (SCs) realized by lattice engineering via annealing in the ambient atmosphere. The engineered α-FAPbI 3 SC detector shows almost all the best figures of merit including a high sensitivity of 4.15 × 10 5 μC Gy air -1 cm -2 , a low detection limit of 1.1 nGy air s -1 , a high resolution of 15.9 lp mm -1 , and a short response time of 214 μs. We further demonstrate high-definition x-ray imaging at a dose rate below 10 nGy air s -1 on the FAPbI 3 SC, indicating a minimal dose-area product of 0.048 mGy air cm 2 to the patient for one-time posteroanterior chest diagnosis, which is more than 3000 times lower than the international reference level of 150 mGy air cm 2 . In addition, the robust long-term stability enables the FAPbI 3 SC x-ray detector to work steadily for more than 40 years.