Abstract: Zero-dimensional (0D) metal halide perovskites with localized exciton environments have emerged as a new generation of high-efficiency luminescent materials. Introducing dopants into these luminescent materials have become a versatile way to tune photoluminescence for various optical application. Here, we report the synthesis of trivalent antimony (Sb³⁺) doped Cs₃CdBr₅ with 0D structure using the solvothermal method. Theoretical calculations indicate that the undoped Cs₃CdBr₅ perovskite has no emission due to the parity-forbidden transitions, whereas Sb³⁺-doped Cs₃CdBr₅ exhibits no forbidden transitions. Experimentally, Sb³⁺ doping significantly enhances the emission quantum yield from 0 % to an impressive 94.14 %. The intrinsic photophysical mechanism of the host-guest system is further elucidated by temperature-dependent photoluminescence spectra. With its excellent luminescence performance and temperature-dependent photoluminescence characteristics, Sb³⁺-doped Cs₃CdBr₅ shows potential for applications in lighting, encryption, and anti-counterfeiting. This work highlights the impact of Sb³⁺ ion doping on the optical properties of 0D metal halide perovskites Cs₃CdBr₅, enabling multi-functional applications through their enhanced luminescence properties.

Key words: Zero-dimensional metal halide, White light-emitting diode, Encryption, Anti-counterfeiting