Fig. 3: SWIR luminescence properties of Lu_0.2Sc_0.8BO₃:Cr³⁺,Yb³⁺ phosphors.

a Photoluminescence emission and excitation spectra of Lu_0.2Sc_0.8BO₃:5%Yb³⁺, Lu_0.2Sc_0.8BO₃:2%Cr³⁺, and Lu_0.2Sc_0.8BO₃:2%Cr³⁺,5%Yb³⁺ phosphors. b Photoluminescence emission spectra of Lu_0.2Sc_0.8BO₃:2%Cr³⁺,yYb³⁺ (y = 0–0.1) upon 463-nm-light excitation. c The ratio of Yb³⁺ (940–1200 nm) SWIR emission to Cr³⁺ NIR emission (650–940 nm), and Cr³⁺ NIR emission intensity and Yb³⁺ SWIR emission intensity in Lu_0.2Sc_0.8BO₃:2%Cr³⁺,yYb³⁺ phosphors with varying Yb³⁺ doping concentration. d Luminescence decay curves of Cr³⁺ in Lu_0.2Sc_0.8BO₃:2%Cr³⁺,yYb³⁺ phosphors monitored at 830 nm with different Yb³⁺ concentration. e Schematic representation of Cr³⁺→Yb³⁺ energy transfer. f The measured Cr³⁺ lifetime and Cr³⁺→Yb³⁺ energy transfer efficiency at different Yb³⁺ concentration