Multiple Photoluminescence Centers in Zero‐Dimensional Antimony Chloride Enable Excitation Wavelength Dependent Broadband Emission for Anti‐Counterfeit Encryption

ABSTRACT Low‐dimensional organic–inorganic hybrid metal halides with excitation‐dependent emission behaviors have emerged as candidate materials for multi‐information and anti‐counterfeit encryption. However, this photoluminescence mechanism stemming from distinct active centers remains a significant challenge. Herein, a pair of antimony halides enantiomers, S ‐ and R ‐(AEEP) 2 (Sb 2 Cl 10 ) (AEEP = 2‐aminomethyl‐1‐ethylpyrrolidine) are presented, in which the isolated [Sb 2 Cl 10 ] 4− dimers are separated by organic cations with a large number of Sb─Cl secondary bonds. Remarkably, both materials exhibit an unusual excitation‐dependent broadband emission spanning from yellow‐ to blue‐light. Systematic optical measurements and theoretical calculations demonstrated that the intriguing excitation‐dependent emission behavior arises from the distinct populations of three types of excitons, corresponding to the organic ligands, vacancy‐bound excitons, and self‐trapped excitons. Furthermore, the multimodal anti‐counterfeiting is further demonstrated by combining multiple excited states of these luminescent materials. This work provides a promising approach to design materials for advanced anti‐counterfeiting applications.