An efficient and thermally stable Cr³⁺-activated Y₂GdSc₂Al₂GaO₁₂ garnet phosphor for NIR spectroscopy applications

Near-infrared (NIR) spectroscopy realized by an NIR phosphor-converted light-emitting diode (pc-LED) as a light source has aroused considerable interest due to its numerous merits and widespread application scenarios. Nevertheless, developing NIR emitting phosphors with high performance is still the top priority. Here, we report a new Y₂GdSc₂Al₂GaO₁₂:Cr³⁺ (YGSAG:Cr³⁺) garnet phosphor, which demonstrates a broadband emission peaking at 754 nm with a full width at half maximum (FWHM) of around 120 nm in the range of 650-1200 nm. The YGSAG:0.08Cr³⁺ sample irradiated by blue light exhibits the most intense emission intensity, leading to a high absorption efficiency of 49.54%. In addition, compared with room temperature, the integrated PL intensity of the sample can still be maintained at 90.97% at 423 K. Benefitting from the outstanding optical properties, the as-manufactured NIR pc-LED device driven by a 100 mA current represents a high NIR output power of 35.14 mW and a photoelectric efficiency of 12.51%. These results verify that the as-synthesized YGSAG:Cr³⁺ phosphor possesses great potential for the applications of NIR spectroscopy.