Luminescence Improvement of Hybrid Zinc-Based Halides via Sb3+-Doping for Flexible X-Ray Imaging

Recently, zinc-based metal halides have attracted numerous attention due to their excellent stability, low toxicity, and wide bandgaps. However, [ZnX₄]²⁻ tetrahedra in zinc-based halides are found to be non-optically active, which leads to poor photoluminescence quantum yields (PLQYs). Herein, Sb³⁺ ions are doped into hybrid zinc-based halides of (C₈H₂₆N₄)ZnCl₆ single crystals (SCs) via an evaporative crystallization method. Compared with undoped (C₈H₂₆N₄)ZnCl₆ SCs with weak blue emission, Sb³⁺-doped (C₈H₂₆N₄)ZnCl₆ SCs exhibit a strong broadband emission centered at 694 nm with a high PLQY of 67%, which is confirmed to be derived from self-trapped excitons (STEs) of Sb³⁺ luminescent centers. Subsequently, Sb³⁺-doped (C₈H₂₆N₄)ZnCl₆ is employed in flexible scintillation films, which demonstrates remarkable X-ray imaging of complex objects with a spatial resolution of 3.6 lp mm⁻¹ and a detection limit of 123.8 µGy_air s⁻¹, proving its promising potential in flexible X-ray imaging applications.