Structural Rigidity Control toward Cr3+-Based Broadband Near-Infrared Luminescence with Enhanced Thermal Stability

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, Cr3+-activated CaSc1-xAl1+xSiO6 (lambda(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 Sc3+/Al3+ substitution contributes to enhancing the structural rigidity and the local symmetry of the [Sc/AlO6] octahedron so that the nonradiative relaxation of Cr3+ emission centers is suppressed significantly. The as-fabricated phosphor-in-glassbased 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.

Automated summary

In this study, broadband NIR phosphors were designed and optimized through chemical substitution to enhance thermal stability and quantum efficiency. The as-fabricated phosphor-in-glass-based NIR LED light source showed potential in alcohol concentration detection. This research provides a design principle for exploring NIR phosphors with improved thermal stability and will stimulate further material discovery and quantitative analysis research in NIR spectroscopy.