Dimensionally Tailored Core-Shell Perovskite Heterocrystals for High-Sensitivity, Low-Drift X-ray Detection and Imaging

Here we report the self-assembly of 3D perovskites and 2D layered perovskites into large core-shell heterocrystals with well-defined interfaces and a controlled shell thickness. The 3D core possesses desirable X-ray responsive optoelectronic properties, while the hydrophobic organic spacers in the 2D shell can suppress ion migration and prevent the direct exposure of the core to moisture. Notably, X-ray detectors using these core-shell heterocrystals exhibit ultralow dark current drift of 1.1 × 10^-7 nA cm^-1 s^-1 V^-1, which is 5 orders of magnitude lower than that of the pristine 3D perovskite devices. Moreover, the devices also display significantly enhanced X-ray response, including high sensitivity of 1 × 10⁴ μC Gy_air^-1 cm^-2, low detection limit of 40 nGy_air s^-1, and the capacity for high-resolution X-ray imaging. By realizing core-shell heterocrystals, this work paves the way for developing high-performance perovskite optoelectronic devices with high stability and sensitivity.