Exploring centimeter-sized crystals of bismuth-iodide perovskite toward highly sensitive X-ray detection

Lead-halide perovskites exhibit outstanding performance in X-ray detection due to their intrinsic features such as high charge carrier mobility, large atomic number, and long carrier lifetime, but the toxicity of lead is regarded as the major factor hindering their development. Here, we introduce organic molecule (R)-(-)-2-methylpiperazine (R-MPz) into the bismuth-based structure to synthesize lead-free (R)-(H2MPz)BiI5 (R-MBI). The high-quality centimeter-sized single crystals have been obtained, which show a low dark current and superior environmental stability. Particularly, the single-crystal device of R-MBI exhibits a high μτ product up to 1.88 × 10−4 cm2/V and a low trap density of 1.21 × 1010 cm−3. Further, the detector displays excellent detection sensitivity of 263.58 μC Gyair−1 cm−2 and a favorable low detection limit of 4.35 μGyair/s, both of which meet the requirement for medical diagnostics. These findings shed light on the exploration of innovative bismuth-based hybrid perovskites for high-performance X-ray detection.