Structural and spectroscopic diagnosis of Eu:ZnO and Eu:Yb:ZnO glass and ceramics

Eu and Eu:Yb codoped ZnO nanocrystals embedded in B2O3 glass matrix were synthesized and their structural, optical properties were discussed. On excitation with 532 nm laser radiation intense orange/red emissions from Eu3+ ions were observed. The fluorescence intensity was found to enhance on annealing. Frequency upconversion emissions from Eu3+ ions were observed in presence of Yb3+ ions on excitation with NIR (976 nm) laser. The enhancement in emission intensity was explained and the photo-physics involved is linked with the unique structural properties of the crystallites formed. Ion interactions and the different energy transfer parameters were also calculated.

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► Eu/Eu:Yb:ZnO nanocrystals were analyzed using XRD, SEM, TEM and optical microscopy.
► Red emission of Eu enhancing ten folds in ZnO nanocrystal on 532 nm excitation.
► Emission enhancement was explained and linked with unique structure of the crystal.
► Cooperative energy transfer (Yb → Eu) yields intense red color on 976 nm excitation.
► Energy transfer and emission dynamics were explained with time resolved spectroscopy.