On–Off Switching of Singlet Self‐Trapped Exciton Emission Endows Antimony‐Doped Indium Halides with Excitation‐Wavelength‐Dependent Luminescence
Xinyu Yang, Hongyuan Zhao, Ziying Wen, Yunfei Bai, Qichao Meng, Haibo Sun, Xihong Ding, Junke Jiang, Dan Huang, William W. Yu, Feng Liu
Abstract
Abstract Excitation‐wavelength‐dependent (Ex‐De) emitters are a fascinating category of luminescent materials whose emission properties vary with the wavelength of the light used for excitation. Antimony (Sb 3+ )‐doped indium (In)‐based metal halides are efficient light emitters; however, the peak fluorescence emission of most Sb 3+ ‐activated In‐halide remains independent of the excitation wavelength. Here, the study introduces a new Sb 3+ ‐doped In‐halide cluster, (BDPA) 2 InCl 5 :Sb (BDPA + = C 15 H 18 N + , benzyldimethylphenylammonium), which demonstrates efficient Ex‐De emission originating from the on–off switchable fluorescence behavior of singlet self‐trapped exciton (STE) in 5‐coordinate Sb 3+ dopant. Interestingly, when excited within the range of 240–370 nm, photoluminescence (PL) spectra of (BDPA) 2 InCl 5 :Sb show both singlet and triplet STE emission. However, under excitation wavelengths of 370 to 420 nm, the singlet STE emission is absent, resulting in a noticeable correlated color temperature change from 1700 to 3800 K. The study provides a new approach to designing color‐tunable Sb 3+ ‐based luminophores, and also presents a novel application scenario for the widely recognized Sb 3+ doping strategy.