Ultrasensitive and Robust CsPbBr₃ Single-Crystal X‑ray Detectors Based on Interface Engineering

Halide lead perovskites have shown great development in recent years for ionizing radiation detection. However, the bias-induced interfacial electrochemical reaction between the perovskite and electrode severely deteriorates detector performance. We report that BCP strongly interacts with Al and constructs a stable Al–BCP chelating interface, resulting in the suppression of a detrimental electrochemical reaction. The fabricated Au/Al/BCP/C₆₀/CsPbBr₃/Au detector shows a low dark current of 3 nA with a stable baseline at an extremely high bias of 100 V (∼100 V mm^–1). The superior high-bias stability enables a high sensitivity of 7.3 × 10⁴ μC Gy_air^–1 cm^–2 at 100 V. Meanwhile, a low detection limit of 15 nGy_air s^–1 at 40 V is achieved due to the reduced noise. The outstanding performance of our device exceeds that of most advanced detectors based on CsPbBr₃ single crystals. Besides, X-ray imaging with 1 mm spatial resolution is well demonstrated at a low dose rate of 200 nGy_air s^–1. The interfacial chelating strategy overcomes the technical limitation of bias-induced instability of perovskite radiation detectors and can be anticipated to operate under an extremely high electrical field.