Broadband emitting Mg3Lu2Ge3O12:Cr3+ phosphors with garnet structure for high-performance NIR LEDs applications

Cr3+-doped phosphors show great application prospects in near-infrared (NIR) LEDs owing to good compatibility with blue LED chips. However, current NIR phosphors still have some shortcomings in the practical application, such as narrowband emissions and low efficiency. Herein, a new Cr3+-doped Mg3Lu2Ge3O12 (MLGO) broadband NIR phosphor has been successfully synthesized. X-ray diffraction and transmission electron microscopy demonstrate the sample crystallizes in the garnet structure with the Ia 3¯ d space group. Under 442 nm excitation, MLGO:0.04Cr3+ represents an broadband emission centered at 770 nm with a full width at half maximum of 158 nm, and has an external quantum efficiency of 12.5%. Moreover, the emission intensity of MLGO:0.04Cr3+ at 125 °C still reaches 50% of that at room temperature. Additionally, a NIR LEDs device is fabricated by combining the sample with a blue LED chip, and has an excellent NIR output efficiency of 13.1%. Under the illumination of the NIR LEDs, clear images can be successfully captured in the dark. Therefore, the MLGO:Cr3+ phosphors can be used for NIR light sources applied in the areas of food analysis and night vision imaging.