Modulating Ultraviolet‐Visible‐Near Infrared Emission in Hybrid Metal Halides via ns ² Ion Doping

Abstract Tunable broad‐spectrum luminescent materials covering the ultraviolet (UV), visible, and near infrared (NIR) regions are essential for next‐generation optoelectronic technologies. However, conventional systems are often limited by inefficient UV emission and the inability to integrate multiple spectral components within a single material. Here, a design strategy that combines ns 2 ‐ion with controlled lattice distortion is introduced to overcome these challenges. Using 4,4‐difluoropiperidine (DFPD) as the organic cation, a family of hybrid metal halide phosphors, [(DFPD) 2 MCl 4 ·H 2 O, M = Cd/Zn] doped with different ns 2 ion (Sn 2+ , Pb 2+ , Sb 3+ , Bi 3+ , and Te 4+ ) is synthesized. It is revealed that reduced lattice distortion correlates with enhanced photoluminescence quantum yield (PLQY), enabling broadband self‐trapped exciton emission spanning the UV–vis–NIR range within a single host matrix. Leveraging the highly efficient UV emission of 2% Pb‐doped (DFPD) 2 CdCl 4 ·H 2 O (PLQY: 93%), a high‐performance white light emitter with a color rendering index of 92.9 and a correlated color temperature of 6087 K is demonstrated. The materials further exhibit promising functionality in NIR imaging and multi‐level anti‐counterfeiting. This work elucidates the interplay between lattice distortion and exciton dynamics in Cd/Zn‐based hybrid metal halides, providing fundamental insights into their photophysics and establishing a versatile strategy for designing next‐generation broadband multifunctional optoelectronic materials.