Molten Salt Synthesis of Single-Crystalline Sr2MgSi2O7: Eu2+, Dy3+ Nanoplates: Breaking the Afterglow-Size Trade-off

Sr2MgSi2O7/Eu2+, Dy3+ (SMSED) phosphors show promise for persistent luminescence applications due to their long afterglow and robust chemical stability. However, a trade-off exists between achieving precise size and shape control of SMSED and maintaining prolonged afterglow intensity and duration during synthesis. Herein, we unveil a molten-salt method that successfully produces uniform single-crystalline plate-like SMSED for the first time. This synthesis significantly reduces both the sintering temperature and time compared to the classic solid–state reaction (SSR) method. Owing to the nanoplates structure, uniform size distribution, and single-crystal nature, the resulting SMSED exhibited excellent afterglow performance and thermal stability, with a sustained blue afterglow exceeding 24 h and retaining >70% of its initial luminescence up to 523 K, outperforming most reported SMSED phosphors. These remarkable properties underscore the considerable potential of SMSED nanoplates for applications in fingerprint detection. This work unlocks a new synthetic frontier for achieving the controllable synthesis of SMSED phosphors, paving the way for future optimizations aimed at the development of advanced persistent luminescent phosphors.