A Novel Dual-mode Broadband Near-infrared Phosphor Mg5Ga2Sn2O12:Cr3+, Ni2+ Designed Based on Energy Transfer Strategy

Near-infrared (NIR) phosphor-converted light-emitting diodes (NIR-pc-LEDs) are considered as ideal next-generation NIR light sources. However, the commercialization of NIR-pc-LEDs has been hindered by the narrow full width at half maximum (FWHM) of the NIR luminescent materials. To address this issue, we designed a novel dual-mode broadband NIR phosphor Mg5Ga2Sn2O12:Cr3+, Ni2+ (MGSO) based on an energy transfer strategy. The optimized MGSO:0.1Cr3+, 0.01Ni2+ shows ultra broadband NIR emission from 700 to 1650 nm under 424 nm excitation. The emission peaks are located at 820 nm (NIR-I region, Cr3+) and 1450 nm (NIR-II region, Ni2+). Rapid energy transfers from Cr3+ to Ni2+ was confirmed through a systematic analysis of the diffuse reflection spectra, excitation spectra, and fluorescence decay curves. The internal and external quantum efficiencies of MGSO:0.1Cr3+, 0.01Ni2+ are 68.2% and 30%, respectively. To further investigate its application prospect, a novel NIR light source was created by encapsulating MGSO:0.1Cr3+, 0.01Ni2+ with a 440 nm blue light LED. The testing results demonstrate its potential for applications in information encryption, bio-imaging, and non-destructive detection of organic solutions. This study provides a new perspective on the development of continuous broadband NIR phosphors.