Effects of Cl/Br substitution of antimony octahedra on photoluminescence and a new engineering strategy for performance optimization

Organic-inorganic metal halides have garnered extensive attention due to their versatile structures as well as fascinating optical properties, among which especially antimony halides are the focus of recent research. Herein, we design a series of novel zero-dimensional (0D) antimony halides of (C₁₃H₁₄N₃)₃SbCl_6–xBr_x (x = 0, 3, 6) with bright and tunable broadband emissions from yellow (576 nm) to orange (600 nm), which are attributed to the triplet self-trapped excitons (STEs) of the six-coordinated SbX₆]^3– (X = Cl^? or Br^?) units. The role of halogens on their specific ³P₁→¹S₀ transition is determined, wherein Cl/Br transmutation reveals a common law modulating photoluminescence behaviors. Furthermore, a new two-step compound technology is innovatively developed for performance optimization, enabling by incorporating the pristine antimony halides into polymethyl methacrylate (PMMA) with high transparency and strong moisture resistance. The composites (C₁₃H₁₄N₃)₃SbCl_6–xBr_x/PMMA (x = 0, 3, 6) were fabricated through a demanding technology that significantly improve the processability and water stability of antimony halides while maintaining high photoluminescence quantum yields. This work not only proposes a method for halogen substitutions to tune emission, but also opens up a feasible research avenue for performance optimization in the multifunctional luminescence materials.