Broadband near-infrared long persistent luminescence in Cr3+-Doped CaY2Ga4GeO12 phosphors for advanced light source applications

Recently, Near-Infrared (NIR) long persistent phosphors (LPPs) have attracted significant attention as promising candidates for diverse applications, including drug delivery, in vivo bio-imaging, and military technologies. However, the substantial degradation in luminescence intensity and persistence time remains a key challenge. Consequently, it is imperative to develop more competitive LPPs that exhibit both high luminescence intensity and extended persistence time. In this work, we present a novel NIR LPP, CYGGO: Cr 3+ , which demonstrates broadband NIR emission spanning 650–1150 nm, with an emission maximum at 792 nm and a full width at half-maximum (FWHM) of 155 nm under 448 nm excitation. Notably, the NIR signal persists for over 12 h following the cessation of UV light excitation. Comprehensive investigations have been conducted on the crystal and electronic structures, thermal stability, as well as the photoluminescence properties and mechanisms of this phosphor. Additionally, the NIR LPP properties and mechanisms have been thoroughly examined. The trap types and depths in CYGGO:Cr 3+ were also analyzed through thermoluminescence glow curve studies. Collectively, these results indicate that CYGGO:Cr 3+ phosphors hold significant promise for future applications as NIR persistent light-emitting sources.