Spinel-type persistent luminescence nanoparticles: From mechanisms, compositions to applications

Spinel-structure persistent luminescence nanoparticles (SS-PLNPs) have attracted considerable interest due to their magical afterglow emission. SS-PLNPs constitute spinel host, emission center, and trap, while the host is the carrier of trap and emission center. The inherent defects of spinel host can store and release charge carriers for persistent luminescence, while the introduction of emission center enriches their optical properties greatly. Trap captures charge carriers, which are stored and then released gradually to produce the afterglow emission. Besides the unique afterglow emission, SS-PLNPs exhibit abundant composites, various energy transfer mechanisms, and tunable optical properties. Thus, they are extensively applied in various fields, including but not limiting sensing, biomedicine, information recognition, photocatalysis, and solar cell. This review summarizes the emission mechanisms, synthesis methods, compositions, and applications of SS-PLNPs in depth. The challenges related to SS-PLNPs are also discussed.