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RESEARCH PRODUCT

ZnO – Yb2O3 composite optical ceramics: Synthesis, structure and spectral-luminescent properties

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description

International audience; Zinc oxide optical ceramics containing 0 – 2 wt% ytterbium are prepared byuniaxial hot pressing of commercial oxides at 1150 and 1180 °C. The ceramics have themain crystalline phase of hexagonal wurtzite-type ZnO. Ytterbium ions do not enter theZnO crystals but form a cubic sesquioxide phase of Yb2O3 located at the ZnO grainboundaries. Yb acts as an inhibitor for the ZnO grain growth. The ceramics exhibittransmittance up to 60% in the visible. Their transmission in the infrared is determinedby the free charge carrier absorption. The Yb3+ ions are found in C2 and C3i sites in Yb2O3crystals. Under X-ray excitation, the ceramics exhibit intense luminescence bands in theblue (near-band-edge emission) and green (defect emission) whose positions, intensitiesand decay times depend on the Yb content. Yb2O3 causes a redistribution of luminescenceintensity in favor of the near-band-edge emission and fastens the emission decay.