Broad-range emission color tuning in zero-dimensional hybrid metal halides via Sb3+ local structure regulation

Local structure regulation provides an effective route to manipulate the excited-state structures and emission properties of Sb3+-activated zero-dimensional (0D) organic-inorganic hybrid metal halides. Herein, we develop a local structure regulation strategy in a series of 0D hybrid metal halides sharing the same C13H22N+ organic cation. By regulating the coordination geometry and halide ligands of Sb3+ centers, distinct Sb3+ local coordination structures are constructed, enabling broad emission color tuning from blue at 442 nm to deep red at 710 nm. Photophysical characterizations and first-principles calculations reveal that the emission evolution is governed by the coupled modulation of spin-orbit coupling (SOC) and electron-phonon coupling. In particular, the coordination environment influences the heavy-atom effect and intersystem crossing (ISC) process, thereby altering the relative contributions of singlet-state and triplet-state self-trapped exciton emissions. Furthermore, a transparent emissive hybrid glass with a visible-light transmittance of up to 88% is obtained by melt-quenching, demonstrating excellent processability for fabricating high-performance optoelectronic devices. This work establishes local structure regulation as a practical strategy for controlling exciton dynamics and designing Sb-based 0D metal halides with broadly tunable emission colors.