Low-dimensional metal halides have attracted extensive attention due to their excellent optical properties, especially zero-dimensional metal halides, which can improve the radiation recombination probability due to the characteristics of their isolated octahedral structures. In this paper, we report a zero-dimensional metal halide Sb ³⁺doped Rb ₇Bi ₃Cl ₁₆with a broadband orange-yellow emission at 613 nm. When the Sb ³⁺doping concentration is 30%, the highest photoluminescence quantum yield of the system reaches 30.7%. This high-efficiency luminescence is derived from the self-trapped excitons generated by the strong interaction between electrons and the crystal lattice. The specific physical mechanism and energy transfer process of self-trapped exciton luminescence are further studied through characterizing the optical performances. The electronic states in the singlet ¹P ₁level are relaxed to the triplet ³P ₁via an intersystem crossing process, and the strong orange-yellow emission comes from the triplet state ³P ₁→ ¹S ₀radiation recombination process. In addition, Sb ³⁺doped Rb ₇Bi ₃Cl ₁₆has satisfactory environmental stability, the Sb ³⁺:Rb ₇Bi ₃Cl ₁₆-based light-emitting diodes (LED) are fabricated here in this work, and the color coordinates and correlated color temperature of the LED are (0.4886, 0.4534) and 2641 K, respectively. The highly efficient and stable Sb ³⁺doped Rb ₇Bi ₃Cl ₁₆is expected to be used in solid-state lighting and display fields.