Photoluminescence properties of Li3Sc1-x(BO3)2:xCr3+ phosphors and enhanced near-infrared emission and thermal stability by Yb3+ codoping

Cr 3+ activated broadband near-infrared (NIR) emitting phosphors have attracted more attention worldwide as they are strongly expected to be promising light convertors for phosphor-converted NIR light sources for NIR spectroscopy and imaging technologies. Herein, a new broadband NIR emitting phosphor Cr 3+ -doped Li 3 Sc(BO 3 ) 2 (LSBO) is introduced. Microcrystalline powders of LSBO doped with different Cr 3+ concentrations were synthesized by solid-state reactions and showed an NIR emission extending from 700 to 1100 nm with a peak at 830 nm upon excitation at 460 nm. The structure, concentration and temperature-dependent luminescence properties of LSBO:Cr 3+ phosphors were discussed in detail. The optical properties of Cr 3+ ions in LSBO were examined in terms of spectroscopic parameters. Moreover, efficient energy transfer from Cr 3+ to Yb 3+ was leveraged to significantly improve the NIR emission intensity and the thermal stability. The enhancement and energy transfer mechanisms have been discussed in detail. These results open up new ways to realize efficient NIR-emitting materials.