High‐Performance Tunable Near‐Infrared Emitters of Cr <sup>3+</sup> ‐Activated Garnet Phosphor Enabled by Chemical Unit Co‐Substitution
Ling Liu, Ye Yang, Linawa Shen, Shichang Song, Jinling Huang, Fuwang Mo, Qi Pang, Peican Chen, Liya Zhou
Abstract
Abstract The escalating demand for portable near‐infrared (NIR) light sources has posed a formidable challenge to the development of NIR phosphors characterized by high efficiency and exceptional thermal stability. Taking inspiration from the chemical unit co‐substitution strategy, high‐performance tunable (Lu 3‐ x Ca x )(Ga 5‐ x Ge x )O 12 :6%Cr 3+ ( x = 0–3) phosphors are designed with an emission center from 704 to 780 nm and a broadest full width at half maximum (FWHM) of up to 172 nm by introducing Ca 2+ and Ge 4+ ions into the garnet structure. In particular, Lu 3 Ga 5 O 12 :6%Cr 3+ demonstrates an anti‐thermal quenching phenomenon ( I 423K = 113.1%). Compared to Lu 3 Ga 5 O 12 :6%Cr 3+ , Lu 2 CaGa 4 GeO 12 :6%Cr 3+ exhibits significantly improved FWHM and IQE by 108 nm and 25.5%, respectively, while maintaining good thermal stability ( I 423K = 80.4%). Finally, Lu 2 CaGa 4 GeO 12 :6%Cr 3+ phosphor is combined with a 465 nm blue LED chip to fabricate NIR LED devices, exhibiting a NIR electroluminescence efficiency of 13.31%@100 mA and demonstrating successful applications in nocturnal illumination and biomedical imaging technology. This work offers a fresh perspective on the design of highly efficient NIR garnet phosphors.