Cr3+-Yb3+ energy transfer drives ultra-wideband thermally-stable NIR-emitting Sr3Sc2Ge3O12 garnet phosphors for pc-LED application

The development of medical, military, and other fields has greatly increased the demand for broadband near-infrared light sources . This article reports that Sr 3 Sc 2 Ge 3 O 12 : Cr 3+ (SSGO: Cr 3+ ), a broadband near-infrared phosphor with 850 nm as the luminescence center, has an emission spectrum covering 700–1200 nm and a full width at half maximum (FWHM) of 125 nm under 490 nm excitation. To further increase the FWHM value, Yb 3+ is introduced into the phosphor of SSGO: Cr 3+ to enable energy transfer from Cr 3+ to Yb 3+ . After doping 1 % of Yb 3+ onto the Sr 2+ site, the near-infrared emission generated by the 4 A 2 → 4 T 1 (4P) transition of Cr 3+ and the near-infrared emission generated by the 2 F 5/2  →  2 F 7/2 transition of Yb 3+ work so that the FWHM increases to 220 nm. In addition, the thermal stability of the phosphor after co-doping with Yb 3+ is also greatly enhanced from 61.6 % to 75.1 % by comparing it to the Cr 3+ single-doped sample. In addition, SSGO:0.08Cr 3+ , 0.01 Yb 3+ was combined with a commercial 490 nm chip to prepare a broadband near-infrared light-emitting diode (pc-LED).