Tunable near-infrared phosphor LiSc2SbO6:Cr3+ by Mg2+ substitution and Yb3+ co-doping for phosphor-converted light-emitting diodes†

Near-infrared (NIR) phosphors have been extensively used in the fields of biological imaging, night vision monitoring, and food safety inspection. Although Cr³⁺ doping phosphors have been widely reported, achieving broadband and tunable NIR emissions remains challenging. In this work, Cr³⁺-doped LiSc₂SbO₆ broadband NIR phosphors were synthesized by a high-temperature solid-phase method. LiSc₂SbO₆:Cr³⁺ exhibits a wide emission band of 780–1400 nm. By [Mg²⁺–Mg²⁺] co-substituting the [Li⁺–Sc³⁺] chemical units, controllable emission is achieved with the emission peak tuning in the range of 890–950 nm, FWHM in the range of 215–239 nm, and the maximum intensity increased by 1.51 times. On co-doping with Yb³⁺ ions, the luminous intensity of the Li_0.7Mg_0.6Sc_1.7SbO₆:0.02Cr³⁺,0.05Yb³⁺ (LMSS:Cr³⁺,Yb³⁺) phosphor has been further enhanced by 5.62 times. Thus, the LMSS:Cr³⁺,Yb³⁺ phosphor has great potential in the field of anti-counterfeiting and information encryption. By combining LMSS:Cr³⁺,Yb³⁺ with a commercial blue LED chip, the obtained NIR pc-LED performs well in night vision and non-destructive testing applications.