Chromium(III)-Doped Phosphors of High-Efficiency Two-Site Occupation Broadband Infrared Emission for Vessel Visualization Applications

The exploration of efficient broadband near-infrared (NIR) emitting materials is essential to establishing new NIR applications. In this work, an excellent NIR phosphor Mg₇Ga₂GeO₁₂:Cr³⁺, with an emission band of 650–1350 nm and a full width at half maximum of 266 nm, was successfully prepared. When Ga³⁺ ions were replaced by In³⁺ ions, its emission intensity increased 4 times, and the internal and external quantum efficiency reached 86 and 37%, respectively. A NIR phosphor-converted light-emitting diode (pc-LED) component was made by combining a synthetic Mg₇Ga_1.84In_0.07GeO₁₂:0.09Cr³⁺ phosphor with a 450 nm blue luminescent chip. The vascular and skeletal distribution on human fingers and the back of the hand can be seen under the display of a commercial NIR camera, indicating that Mg₇Ga_1.84In_0.07GeO₁₂:0.09Cr³⁺ phosphors have promising applications in the field of the blood vessel and bone visualization.