Microstructure and luminescence of Yb3+-doped fluorosilicate glass ceramics

Yb3+-doped transparent glass ceramics containing cubic SrF2 nanocrystals were prepared by heat treating the precursor fluorosilicate glass. The precipitated crystals increase in size and the crystallinity decreases with increasing Yb3+ doping level. With high-resolution transmission electron microscopy and electron diffraction, the nano-sized nature of SrF2 was clearly observed. Owing to a significant change in the crystal-field effects with Yb3+ enriching in the SrF2 phase, the glass ceramics present near infrared emission with large bandwidths and long lifetimes, simultaneously. This indicates the glass ceramics have potential application in the efficient IR lasers pumping by InGaAs diodes. The glass ceramics can also emit blue upconversion luminescence, deriving from Yb3+ pairs’ cooperative luminescence. It suggested that Yb3+ can be an efficient upconversion sensitizer for other rare earth ions.