Enhanced luminescence performance of near-infrared phosphor Y2CaAl4SiO12: Fe3+, Yb3+ through energy transfer for anti-counterfeiting applications

Environment-friendly Fe³⁺ions as near-infrared (NIR) activators have garnered significant attention in intelligent NIR light sources; however, designing wavelength-tunable and outstanding thermal stability Fe³⁺-doped NIR luminescent materials remains a formidable challenge. In this study, we synthesized a novel garnet-structured NIR phosphor Y2CaAl4SiO12: Fe³⁺, Yb³⁺and investigated its luminescent properties and energy transfer mechanisms. Under 270 nm ultraviolet light excitation, Y2CaAl4SiO12: Fe³⁺demonstrates broadband NIR emission peaking at 803 nm, characterized by a full width at half maximum (FWHM) of 107 nm and exhibiting a remarkably high internal quantum efficiency (IQE) of 91.70 %, which is markedly superior to most reported Fe³⁺doping NIR-emitting materials. Notably, the incorporation of Yb³⁺ions facilitates an efficient energy transfer process from Fe³⁺to Yb³⁺, which not only significantly broadens the emission spectrum but also enhances the thermal stability of Fe³⁺(I373 K/I298 K = 59.24 %) compared to the singly Fe³⁺doped sample (I373 K/I298 K = 45.30 %). Finally, the optimized Y2CaAl4SiO12: Fe³⁺, Yb³⁺NIR phosphor exhibits promising potential for anti-counterfeiting applications.