Ultrabright Sb³⁺-Based Zero-Dimensional Hybrid (DTA)₂SbCl₅: Dual-Band Self-Trapped Exciton Emission Mechanism Validated by Orbital-Composition Analysis

To overcome toxicity and instability in lead halides, Sb-based hybrids emerge as alternatives due to low toxicity and high stability. However, current mechanistic studies of Sb-halide luminescence primarily rely on experimental characterization combined with the density of states (DOS) and band structure, lacking atomic orbitally resolved insights from excited-state calculations. We report a novel zero-dimensional (0D) Sb-hybrid, (DTA) 2 SbCl 5, exhibiting bright-orange dual emission (480/630 nm) with a photoluminescence quantum yield (PLQY) of 91.4% and exceptional stability. Combined experimental characterization and atomic orbital analysis attribute the dual peaks to singlet and triplet self-trapped exciton (STE) transitions. By innovatively integrating molecular dynamics (MD) simulations with atomic orbital composition analysis, we explain the phenomenon of switching dominance between singlet and triplet states with increasing temperature. This work establishes a robust methodology for probing photophysical mechanisms in Sb 3+ -based hybrids via postprocessing atomic orbital analysis, providing critical insights for designing ecofriendly optoelectronic materials.