Highly efficient Fe(3+)-doped A(2)BB′O(6) (A = Sr(2+), Ca(2+); B, B′ = In(3+), Sb(5+), Sn(4+)) broadband near-infrared-emitting phosphors for spectroscopic analysis

Near-infrared (NIR)-emitting phosphor-converted light-emitting diodes have attracted widespread attention in various applications based on NIR spectroscopy. Except for typical Cr(3+)-activated NIR-emitting phosphors, next-generation Cr(3+)-free NIR-emitting phosphors with high efficiency and tunable optical properties are highly desired to enrich the types of NIR luminescent materials for different application fields. Here, we report the Fe(3+)-activated Sr(2−y)Ca(y)(InSb)(1−z)Sn(2z)O(6) phosphors that exhibit unprecedented long-wavelength NIR emission. The overall emission tuning from 885 to 1005 nm with broadened full-width at half maximum from 108 to 146 nm was realized through a crystallographic site engineering strategy. The NIR emission was significantly enhanced after complete Ca(2+) incorporation owing to the substitution-induced lower symmetry of the Fe(3+) sites. The Ca(2)InSbO(6):Fe(3+) phosphor peaking at 935 nm showed an ultra-high internal quantum efficiency of 87%. The as-synthesized emission-tunable phosphors demonstrated great potential for NIR spectroscopy detection. This work initiates the development of efficient Fe(3+)-activated broadband NIR-emitting phosphors and opens up a new avenue for designing NIR-emitting phosphor materials.