Co-doped long persistent luminescence materials LiSr3SiO4Cl3:Eu2+,Ln3+ (Ln = Dy, Ho, Er): construction and verification of VRBE and HRBE scheme and their multifunctional applications

Abstract

Long persistent luminescence (LPL) hosts are important and necessary, but they and their trap mechanism have not been researched enough. Moreover, the traditional high-temperature (over 1000 °C) solid-phase synthesis method conflicts with energy saving. In this work, novel LPL materials LiSr₃SiO₄Cl₃:Eu²⁺,Ln³⁺ (Ln = Dy, Ho, Er), which contain the perfect trap depth (0.89–1.20 eV) for information storage, were synthesized at 650 °C. By combining the refined chemical shift model, optical spectroscopy, and thermoluminescence, the host-referred and vacuum-referred binding energy (HRBE and VRBE) of LSSOC were constructed and verified. The decay time originating from the 499 nm emission of LSSOC:Eu,Ho exceeded 20 h. Furthermore, under partial 808 nm and 980 nm near infrared laser photo-stimulated luminescence (NIR PSL) or comprehensive thermally-stimulated luminescence (TSL), LSSOC:Eu,Ho always shows excellent LPL performance. Finally, the application potential of LSSOC:Eu,Ho was verified by fabricating information storage models and anti-counterfeiting labels, which can work under photoluminescence (PL), LPL, PSL, and TSL modes, and the LPL mechanism is also discussed. This work not only provides a new excellent candidate LPL host, but also enriches our understanding of LPL luminescence and the trap mechanism, which provides a new option for multifunctional applications of LPL materials.