Microstructure and upconversion luminescence of Yb3+ and Ho3+ co-doped BST thick films
ABSTRACT 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 100min the BST thick films are polycrystalline with
a perovskite structure. The upconversion luminescence properties of the RE-doped BST thick films under 800nm excitation at
room temperature were investigated. The upconversion emission bands centered at 470 and 534nm 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 2mol% Yb3+ and 0.250mol% Ho3+ ions. All the results show that the BST thick films co-doped with Yb3+ and Ho3+ may have potential use for photoelectric devices.