Ultrabroadband NIR Phosphor CaMg2Sc2Ge3O12:Cr3+ for Multifunctional Applications

Abstract

In this work, the high-efficiency broadband garnet-structured NIR phosphor, CaMg₂Sc₂Ge₃O₁₂:Cr³⁺ (CMSGO:Cr³⁺), has been synthesized using a high-temperature solid-phase method. Under 455 nm excitation, CMSGO:Cr³⁺ exhibits a red to near-infrared (NIR) emission with an ultra-broad range of 600–1400 nm and a maximum full width at half maximum (FWHM) of 273 nm. The Cr³⁺ ions are found to occupy dodecahedral and octahedral sites in CMSGO, demonstrating good thermal stability with the emission at 375 K maintaining 72% of that at room temperature. The NIR phosphor-converted light emitting diode (pc-LED) combining CMSGO:Cr³⁺ phosphor with a 460 nm chip exhibits excellent optical performance, an output power of 80 mW@400 mA, and a photoelectric conversion efficiency of 15.69%@20 mA. Furthermore, the vein of the hand, palm, fingers, and wrist can be clearly observed under the NIR pc-LED device from the CMSGO:Cr³⁺ phosphor. The food testing such as the fish and fruit is operated and the night vision under the NIR pc-LED device is improved obviously. All the results demonstrate the CMSGO:Cr³⁺ phosphor is an excellent candidate in the NIR pc-LED device for rapid medical examination imaging, non-destructive testing, and night vision.