Quasi-Continuous Defect Levels in Broadband Gap: A New Strategy for High-Temperature Long Persistent Luminescence Materials

Long persistent luminescence (LPL) materials widely employed in the fields of emergency lighting and anti-counterfeiting are mostly used at room temperature. As temperatures rise, the performance of LPL materials deteriorates dramatically, which hinders their application in in vivo imaging, high-temperature display, and information storage. Herein, a multifunctional material LiGa5O8:Tb3+ (LGT) with green high-temperature LPL (HT-LPL) and blue cathodoluminescence (CL) is reported. Its LPL performance is anomalously enhanced with increasing temperature, and the duration time is more than 8 h at 423 K. With combined temperature-dependent decay curves and thermoluminescence analyses, the unique quasi-continuous defect levels are found in the band gap. The high-concentration carriers in deep traps are frozen at room temperature and activated only at high temperatures, accompanied by changes in energy transfer pathways. The excellent HT-LPL makes LGT a light-emitting component of next-generation smart wearable devices, as well as high-temperature warning equipment in deep well exploration at a depth of 4500 m. The intense anti-degradation blue CL makes it suitable for field emission displays, while the manipulable emission property makes it suitable for high-level anti-counterfeiting. This study fills a gap in HT-LPL materials and opens up a new gateway for the efficient design of HT-LPL and other multifunctional materials. Through trap control engineering, the unique quasi-continuous defect levels are introduced in the broadband gap material LiGa5O8. The carrier activation states and transfer pathways are influenced by the ambient temperature. This research provides a new strategy to construct high-temperature long persistent luminescence (HT-LPL) materials and demonstrates the application prospects of LiGa5O8:Tb3+ (LGT) in deep well exploration and smart wearable devices.image