Near-infrared phosphor development and broad-range regulation of Cr3+ luminescence via Ca2+/Si4+ incorporation in Y3Ga3Al2O12 garnet

To develop Cr 3+ -activated broadband near-infrared (NIR) phosphors emitting beyond 780 nm with a full-width at half-maximum (FWHM) > 150 nm for multifunctional applications, novel Y 3− x Ca x Ga 3 Al 2− x Si x O 12 : y Cr 3+ were developed by Ca 2+ /Si 4+ co-substitution in the Y 3 Ga 3 Al 2 O 12 garnet host. Both higher Ca 2+ /Si 4+ substitution and greater Cr 3+ incorporation weaken the crystal field strength, red-shift and broaden the Cr 3+ emission band, and shorten the fluorescence decay. Accordingly, the emission maximum and FWHM of this series can be effectively modulated over 708−827 nm and 78−208 nm, respectively. Further, the satisfactory luminescence (output power of 30.31 mW and photoelectric conversion efficiency of 10.75% at a 100 mA drive) and imaging performance of the as-fabricated device using the typical x  = 1.5/ y  = 0.03 sample demonstrated that this phosphor is a candidate material for the construction of pc-NIR-LED, which can be practically deployed in a range of scenarios, including night-vision imaging, food-quality inspection, and non-invasive bioimaging.