Synergistic Energy Transfer and Electron-Capture Competition for Giant Enhancement of Red Persistent Luminescence in LiYGeO4:Mn2+ via Bi3+ Doping

Exploring efficient strategies to enhance persistent luminescence (PersL) is highly demanded to facilitate advanced applications of inorganic PersL phosphors. In this work, a remarkable enhancement of Mn 2+ PersL in LiYGeO 4 (LYGO) with tunable wavelengths is achieved through Bi 3+ codoping. The Mn 2+ emission can be tuned from 600 to 664 nm by increasing the doping concentration, attributed to site-selective occupation of different crystallographic sites. The pronounced enhancement in the PersL of Mn 2+ is achieved through the synergistic interplay of energy transfer from Bi 3+ to Mn 2+ and electron-capture competition between the two hole-trapped ions. Specifically, the PersL intensity of LYGO:0.5%Mn 2+ ,0.125%Bi 3+ at 30 s increased by 444 times compared to that of LYGO:0.5%Mn 2+ after 254 nm excitation. Thermoluminescence measurement reveals that introduction of Bi 3+ creates an additional trap center with depth of 0.60 eV. Moreover, LYGO:Mn 2+ ,Bi 3+ exhibits excellent water resistance and shows great potential for applications in information storage and X-ray detection. This work not only demonstrates an intense red PersL phosphor, but also provides an efficient strategy to enhance PersL in inorganic materials via energy transfer and electron-capture competition.