Improving photoluminescence properties of lead-free Cs4SnBr6 zero-dimensional perovskite via Mn2+/Sb3+ Co-doping

Zero-dimensional tin-based halide perovskites have emerged as promising materials for optoelectronic applications owing to their outstanding optical properties. However, improving their PL efficiency and stability remains a significant challenge. Here, we demonstrate a novel codoping strategy by introducing Mn²⁺/Sb³⁺ ions to enhance both the PL intensity and thermal stability of Cs₄SnBr₆ perovskites. Our experiments reveal that Mn²⁺/Sb³⁺ incorporation increases light emission from self-trapped excitons (STEs) in Cs₄SnBr₆, achieving a PL quantum yield of approximately 67.7 %. Additionally, the doped samples show remarkable thermal stability. Detailed analyses, including X-ray diffraction, energy-dispersive spectroscopy, time-resolved PL, and temperature-dependent PL, suggest that the improved emission is driven by Mn²⁺/Sb³⁺-induced distortion of the [SnBr₆]^4- octahedra, which strengthens electron-phonon coupling and increases STE binding energy.