Engineering Broadband Emission of ZnGaAlSbO∶Cr Phosphors for Near-Infrared LED Application.

In phosphor-converted light-emitting diode (pc-LED)-based near-infrared light sources for biochemical analysis and medical diagnostics, phosphors with broadband near-infrared (NIR) emission play an important role, and obtaining such phosphors is a great challenge. Herein, efficient broadband NIR-emitting ZnGaAlSbO:Cr phosphors are developed by introducing Al to gradually replace Ga in the host ZnGaSbO through crystal engineering. Spectral analysis and densitometric calculations show that this homogeneous cation substitution strategy optimizes the local lattice environment and significantly suppresses the nonradiative relaxation of the Cr emission centers, thus exhibiting strong broadband NIR emission properties. In addition, Cr ions show varied low-temperature emissions with notable temperature sensitivity differences among centers. At 90 K, the material achieves a maximum relative sensitivity of 1.45% K, highlighting its potential as a thermosensitive material for low-temperature applications and temperature sensing. The NIR LED light source fabricated based on this material shows a significant response to different liquids in transmission spectral analysis, suggesting its potential for important applications in the identification of organic compounds.