Engineering lattice and defects of nanosized metal halide perovskite via nickel doping for efficient X-ray imaging

Metal halide perovskites (e.g., CsPbBr₃) have emerged as highly promising scintillator materials owing to their superior optoelectronic characteristics. However, their practical deployment is constrained by intrinsic structural instability and nonradiative recombination-induced energy loss. Herein, we show that Ni²⁺ doping constitutes a potent regulatory strategy for synergistically improving the scintillation performance and environmental robustness of CsPbBr₃ perovskite. Various characterizations combined with threotecial calculation indicate that the incorporation of Ni²⁺ dopants triggers lattice contraction, thereby enhancing the resistance to environmental perturbations. Ni-doping also passivates intrinsic defects and traps, leading to marked suppression of nonradiative recombination pathways. This synergy in as-prepared Ni-doped CsPbBr₃ leads to an 11-fold enhancement in photoluminescence intensity and a substantial increase in photoluminescence quantum yield from 56.0% to 93.7%. Notably, it delivers an exceptional light yield of 38428.5 photons MeV^-1, a low detection limit of 64.9 nGy_air s^-1, and superior radiation tolerance. Furthermore, a flexible scintillation screen containing Ni-doped CsPbBr₃ enables high-resolution X-ray imaging with a spatial resolution of 16.6 lp mm^-1, notably surpassing that of the majority of reported perovskite-based scintillators. This study provides profound insights into the pivotal role of metal doping into halide perovskites for enhancing environmental stability in radiation detection technologies.