0D Sb3+-based organic-inorganic hybrid metal halide (OIMH) scintillators have gained significant attention due to their efficient self-trapped exciton (STE) emission. However, the interplay between local structural distortion, defect-states, and STE emission remains insufficiently understood. Herein, two structurally distinct 0D Sb3+-based OIMHs, [HP(o-tol)3]2SbBr5 and [HP(m-tol)3]4SbBr7, are investigated to elucidate structure-property relationships governing exciton dynamics. Specifically, [HP(o-tol)3]2SbBr5 features a highly distorted [SbBr5]2− square pyramid with an active lone pair, whereas [HP(m-tol)3]4SbBr7 contains a symmetric [SbBr6]3− octahedron with an inactive lone pair. Despite stronger distortion, the former exhibits a low photoluminescence quantum yield (PLQY) of 6%, while the latter achieves a high PLQY of 81%. Through combined photophysical analysis and first-principles calculations, we reveal that the stronger distortion induces defect-states, which compete with STE emission and lead to enhanced non-radiative losses. Consequently, [HP(m-tol)3]4SbBr7 demonstrates promising X-ray scintillation performance, with a light yield (LY) of 12200 ± 200 photons MeV−1. This performance enabled the fabrication of flexible [HP(m-tol)3]4SbBr7@SEBS scintillator films, achieving a spatial resolution of 8.0 lp mm−1 and high-quality 2D & 3D X-ray imaging and tomography, offering a promising path for future medical and industrial inspection technologies.
}}, author = {{Liang, Mingli and Liu, Kun and Li, Le and Zou, Mingxin and Zheng, Kaibo and Wang, Sasa and Liu, Shujuan and Liu, Xiangmei and Zhao, Qiang}}, issn = {{2195-1071}}, keywords = {{3D X-ray imaging; Sb-based organic-inorganic hybrid metal halides; Scintillation; Self-trapped exciton}}, language = {{eng}}, number = {{25}}, publisher = {{John Wiley & Sons Inc.}}, series = {{Advanced Optical Materials}}, title = {{Coordination-Dependent Exciton Dynamics and Scintillation in 0D Sb3+-Based Organic-Inorganic Hybrid Metal Halides}}, url = {{http://dx.doi.org/10.1002/adom.71347}}, doi = {{10.1002/adom.71347}}, volume = {{14}}, year = {{2026}}, }