Enhanced Yellow Persistent Luminescence in Sr3SiO5:Eu2+ through Ge Incorporation

The Sr 3 SiO 5:Eu 2+ phosphor has attracted considerable attention for applications in white LEDs owing to its highly efficient yellow emission under violet-blue excitation. We report herein an enhancement of yellow persistent luminescence in Sr 3 SiO 5:Eu 2+ through Ge incorporation. The strongest persistent luminescence intensity is observed for Sr 3 (Si 1– x Ge x )O 5:Eu 2+ with x = 0.005 with a peak emission wavelength at ∼580 nm and a persistent time of ∼7000 s at the 0.32 mcd/m 2 threshold value after UV radiation. A combination of thermoluminescence measurements and density functional theory (DFT) calculations reveals that the afterglow enhancement is due to a significant increase in the number of oxygen vacancies that act as electron trapping centers with appropriate trap depths. This investigation is anticipated to encourage more exploration of Ge Si substitution to design and improve Si-containing persistent phosphors with superior functionalities.