Near-Infrared LuCa₂ScZrGa₂GeO₁₂:Cr³⁺ Garnet Phosphor with Ultra-broadband Emission for NIR LED Applications

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs), as a new generation of NIR lighting sources, have wide prospects in the areas of food analysis and biological and night vision imaging. Nevertheless, NIR phosphors are still limited by short-wave and narrowband emissions as well as low efficiency. Herein, a series of NIR phosphors, LuCa₂ScZrGa₂GeO₁₂:Cr³⁺ (LCSZGG:Cr³⁺), with broadband emissions have been developed and first reported. At 456 nm excitation, the optimized LCSZGG:0.005Cr³⁺ phosphor represents an ultra-broadband emission within the range of 650-1100 nm, peaking near 815 nm with a full width at half maximum of 166 nm. Furthermore, the LCSZGG:0.005Cr³⁺ phosphor possesses good internal quantum efficiency of 68.75%, and its integrated emission intensity at 423 K still retains about 64.17% of that at room temperature. By combining the optimized sample with a blue chip, a NIR pc-LED device is fabricated, which has an excellent NIR output power of 37.88 mW with an NIR photoelectric conversion efficiency of 12.44% under a 100 mA driving current. The aforementioned results demonstrate that these LCSZGG:Cr³⁺ broadband NIR phosphors are expected as NIR light sources.