Enhancement of photoluminescence and upconversion in Er–Yb codoped nanocrystalline glass–ceramics

Oxyfluoride glass ceramics containing CaF2 nanocrystals were prepared with dopants of Er2O3 and Yb2O3 through melt-quenching and proper thermal treatments. Emission spectra, emission decay and energy dispersive X-ray spectroscopy analysis of the glass ceramics indicated the incorporation of rare earth ions into CaF2 nanocrystals. Photoluminescence intensity of the glass–ceramics has been increased more than a hundred times compared with that of the precursor glass. We also obtained enormous enhancement in upconversion emission and relative population increase of the 4F9/2 level by energy transfer process under excitation at 980 nm in resonance with the 2F5/2 of Yb3+ and 4I11/2 of Er3+ ions.

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► Er, Yb-codoped glass–ceramics containing CaF2 nanocrystals were analyzed.
► Distribution of CaF2 nanocrystals and clusters were examined.
► PL of glass–ceramics under UV or NIR excitation was dramatically enhanced.
► TR–PL revealed two Er sites in CaF2 nanocrystal and glass domains.
► We doped Er2O3 and Yb2O3 instead of the previously reported ErF3 and YbF3.