Microstructure and upconversion luminescence of Yb 3+ and Ho 3+ co-doped BST thick films

Journal of Materials Science (Impact Factor: 2.37). 12/2010; 45(24):6819-6823. DOI: 10.1007/s10853-010-4781-0


Ba0.8Sr0.2TiO3 (BST) thick films co-doped with Yb3+ and Ho3+ were fabricated by the screen printing techniques on alumina substrates. The structure and morphology of the BST thick films
were studied by XRD and SEM, respectively. After sintered at 1240 °C for 100 min the BST thick films are polycrystalline with
a perovskite structure. The upconversion luminescence properties of the RE-doped BST thick films under 800 nm excitation at
room temperature were investigated. The upconversion emission bands centered at 470 and 534 nm corresponding to 5F1 → 5I8 and 5F4 → 5I8 transition, respectively were observed, and the upconversion mechanisms were discussed. The dependence of the upconversion
emission intensity upon the Ho3+ ions concentration was also examined; the emission intensity reaches a maximum value in the sample with 2 mol% Yb3+ and 0.250 mol% Ho3+ ions. All the results show that the BST thick films co-doped with Yb3+ and Ho3+ may have potential use for photoelectric devices.

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    ABSTRACT: Powders of Y2O3 co-doped with Yb3+ and Er3+ composed of well-crystallized nanoparticles (30 to 50 nm in diameter) with no adsorbed ligand species on their surface are prepared by polymer complex solution method. These powders exhibit up-conversion emission upon 978-nm excitation with a color that can be tuned from green to red by changing the Yb3+/Er3+ concentration ratio. The mechanism underlying up-conversion color changes is presented along with material structural and optical properties. PACS 42.70.-a, 78.55.Hx, 78.60.-b
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