Broadband NIR Phosphor Ca₂LuScAl₂Si₂O₁₂:Cr³⁺ for NIR LED Applications

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) have promising applications in food analysis, night vision imaging, and biological probes. Developing NIR phosphors with broadband emission and high efficiency has attracted immense interest. Herein, a novel NIR phosphor Ca₂LuScAl₂Si₂O₁₂:Cr³⁺ (CLSAS:Cr³⁺) is reported for the first time. Under the excitation of 442 nm light, CLSAS:Cr³⁺ shows broadband emission from 600 to 900 nm with a full width at half maximum (FWHM) of 142 nm, benefiting from the emissions of two Cr³⁺ centers in CLSAS, which is proved by the spectra and the decay curves. The internal quantum efficiency (IQE) of 73.7% is achieved and, at 423 K, the emission intensity maintains 76% of the value at room temperature. Combining the CLSAS:Cr³⁺ phosphor and the 450 nm blue chip, the NIR pc-LED is fabricated and demonstrated for fast imaging of veins in human palm and fist, as well as night vision for objects.