Efficient UV Emission with Anti‐Thermal Quenching from Ce ³⁺ ‐Activated 0D All‐Inorganic Zinc Halides

Abstract Inorganic metal halide perovskites have emerged as a prominent research focus in the field of visible‐region optoelectronic devices. However, exploring the ultraviolet (UV)‐emitting inorganic metal halide perovskites with both high efficiency and excellent thermal stability is still a large challenge. Herein, a robust anti‐thermal quenching UV‐emitting material, Ce ³⁺ doped 0D Cs ₂ ZnBr ₄ is reported, exhibiting doublet emission peaks at 342 and 367 nm with a photoluminescence quantum yield of up to 97.0%. Specifically, the Ce ³⁺ doping imparts abnormal anti‐thermal quenching from 303 to 373 K with thermally enhanced 1.8 fold luminescence. Thermoluminescence spectra and density functional theory calculations demonstrate that the behavior originated from the effective compensation of the thermally activated defect levels to the Ce ³⁺ 5d‐band. Furthermore, A bright UV light‐emitting diode based on Cs ₂ ZnBr ₄ :Ce ³⁺ is fabricated, achieving an external quantum efficiency of up to 0.81% and displaying exceptional stability with a long half‐lifetime of 528 h. Thus, this work not only provides a design strategy for abnormal anti‐thermal quenching UV‐emitting phosphors with high efficiency but also paves a new way for cost‐effective, high‐power UV light‐emitting diodes.