Double‐Site Occupation Triggered Broadband and Tunable NIR‐I and NIR‐II Luminescence in AlNbO<sub>4</sub>:Cr<sup>3+</sup> Phosphors
Kuangnan Lyu, Gaochao Liu, Мaxim S. Моlokeev, Zhiguo Xia
Abstract
Abstract Near‐infrared (NIR) phosphor‐converted light‐emitting diodes (pc‐LEDs) are desired for optoelectronic and biomedical applications, while the development of target broadband NIR phosphors still remains a significant challenge. Herein, a kind of Cr 3+ ‐doped AlNbO 4 phosphors with a broad NIR emission ranging from 650 to 1400 nm under 450 nm excitation are reported. A giant red‐shift emission peak from 866 to 1020 nm together with broadened full width at half‐maximum of 320 nm is achieved simply by varying the doped Cr 3+ concentrations. Structural and spectroscopy analysis demonstrate that a concentration‐dependent site‐occupation of Cr 3+ emitters in different Al 3+ sites is responsible for the tunable NIR luminescence. The as‐fabricated NIR pc‐LED based on optimized AlNbO 4 :Cr 3+ phosphor exhibits great potential in night‐vision applications. This work provides a novel design principle on the Cr 3+ ‐doped AlNbO 4 phosphor with tunable broadband luminescence from NIR‐I to NIR‐II, and these materials can be employed in NIR spectroscopy applications.