摘要
Materials exhibiting long-persistent luminescence(LPL)in the visible spectrum hold pivotal importance for anti-counterfeiting and encryption.Nevertheless,conventional LPL materials generally possess a fixed afterglow color.This constraint makes it imperative to develop multimodal luminescent systems featuring spectrally tunable afterglow.Herein,the Er^(3+)/Sm^(3+)co-doped Ca_(3)Ga_(4)O_(9) phosphors achieve multicolor photoluminescence(PL),upconversion luminescence(UCL),and color-tunable LPL by responding to multiple excitations modes ranging from ultraviolet(UV)to near-infrared radiation(NIR).Spectral analysis reveals a green-to-orange multicolor afterglow by varying the relative concentrations of Er^(3+)and Sm^(3+)ions.To unravel the mechanism of multicolor afterglow,afterglow spectra and thermoluminescence(TL)spectra are systematically employed to probe the trap distribution mediated by Er^(3+)and Sm^(3+)co-doping.Finally,their prospective application in optical anti-counterfeiting and information encryption is also systematically investigated based on the color-tunable LPL.This successful integration of multicolor,multimodal luminescence with color-tunable afterglow in a single host provides a novel platform for anticounterfeiting and encryption,significantly expanding the visual diversity of displayable information.
基金
supported by the National Natural Science Foundation of China(Grant No.21871122).
