X-ray detectors are widely used in medical diagnosis, environmental monitoring, safety inspections. In recent years, the organic-inorganic lead halide perovskites with low cost and facile preparation process have shown excellent properties in direct X-ray detection.

However, the issues raised by the toxic lead element and marginal stability due to the volatile organic components have limited their potential applications.

Recently, a research team led by Prof. LIU Shengzhong from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences reported a lead-free perovskite Cs₃Bi₂I₉ single-crystal for high-performance X-ray detection.

They developed a nucleation-controlled solution method to grow large-size, high-quality Cs₃Bi₂I₉ perovskite single crystals (PSCs). Using the technique, they could harvest some centimeter-sized single crystals and achieved high device performance.

The X-ray detectors based on the Cs₃Bi₂I₉ single crystals exhibited high sensitivity and very low detectable dose rate, both are desired in medical diagnostics.

In addition, the X-ray detectors showed high X-ray imaging capability due to its negligible signal drifting and extremely high stability.

Furthermore, the outstanding thermal stability of the Cs₃Bi₂I₉ PSCs was inspired to develop a high-temperature X-ray detector with stable response at up to 100°C.

Their findings were published in Nature Communications.

The Cs₃Bi₂I₉ perovskite single crystal based X-ray detector. (Image by DUAN Lianjie and ZHANG Yunxia)