Structural Rigidity Control toward Cr~(3+)-Based Broadband Near-Infrared Luminescence with Enhanced Thermal Stability

摘要

Broadband near-infrared (NIR) light sources based on phosphor-converted light-emitting diodes (pc-LEDs) are desirable for biochemical analysis and medical diagnosis applications; however, the development of target NIR phosphor is still a challenge. Herein, broadband NIR phosphors, Cr~(3+)-activated CaSc_(1-x)Al_(1+x)SiO6 (λ_(em) = 950 nm), are designed and optimized by chemical substitution toward enhanced quantum efficiency and thermal stability. Structural and spectral analyses along with density functional theory calculations reveal that Sc~(3+)/Al~(3+) substitution contributes to enhancing the structural rigidity and the local symmetry of the [Sc/AlO6] octahedron so that the nonradiative relaxation of Cr~(3+) emission centers is suppressed significantly. The as-fabricated phosphor-in-glass-based NIR LED light source demonstrates great potential in the detection of alcohol concentration. This study provides a local structure design principle for exploring NIR phosphors with enhanced thermal stability and will also stimulate further studies on material discovery and quantitative analysis of NIR spectroscopy.