Boosting luminescence in oxide phosphors by the vitrifying-devitrifying approach

Vitrification-devitrification process often results in the formation of translucent/transparent bulk glass-ceramics/ceramics with functionalities comparable to their crystalline counterparts. Here we show a significant enhancement and tunability of luminescence in Mg2Al4Si5O18+1.5x:xEu2+ (MAS:xEu) powders after being subjected to a vitrification-devitrification protocol. In MAS:xEu powders, Eu2+ occupies multiple-sites in MAS hollow channels, demonstrating tunable blue-to-yellow emissions with red-afterglow. After vitrifying-devitrifying MAS:xEu powders, the derived ceramics showcase red-emissions with a near-unity luminescence efficiency, higher-thermal stability, and longer-persistent luminescence, enabling the fabrication of red-emitting lighting device with an ultrahigh brightness. The luminescence enhancement is ascribed to the increase of oxygen-related defects in the network during vitrification process that facilitates an efficient trapping-detrapping process. From structural analyses, the luminescence tunability can be attributed to the change in the heterogeneous structure of the channel wall, amending the distribution of Eu2+ multiple-sites. Thus, our approach has opened a new avenue for advancing the design of high-performance luminescent materials. In this work, the luminescence performance of oxide phosphors was significantly improved and tuned through a vitrification followed by crystallization protocol. This enabled the fabrication of a high-power solid-state lighting device.