Self-Powered X-ray Detectors Enabled by Perovskite P-I-N Heterojunction

Metal halide perovskites (MHPs) have demonstrated exceptional potential for next-generation X-ray detection due to their superior linear attenuation coefficients, high resistivity, and excellent carrier transport properties. However, practical applications are limited by operational stability issues, particularly ion migration under high electric fields and interfacial degradation in conventional metal-semiconductor-metal (MSM) structures. Here, we propose a p-i-n device configuration that simultaneously optimizes interfacial contacts and electric field distribution. Centimeter-sized MAPbBr₃ single crystals with low defect density (9.56 × 10⁹ cm⁻³) were synthesized via inverse-temperature crystallization, integrated with ZnO and PEDOT:PSS layers to establish a stepped energy band alignment that facilitates charge separation while eliminating direct metal-perovskite contact. Finite element simulations reveal that the p-i-n architecture significantly reduces local electric field intensity, mitigating ion migration. Under 0.238 mGy_airs^-1 @ 0 V, p-i-n device shows great photoelectric responsiveness with a responsivity of 1.02 μC Gy_air⁻¹cm⁻². This dual-optimization also enables stable high-bias operation, achieving a record responsivity of 1.51 × 10⁶ μC Gy_air⁻¹cm⁻². The work highlights the critical role of interface engineering and field distribution control in advancing perovskite-based X-ray detectors toward practical high-responsivity and high-stability applications.