Fabrication, microstructure and upconversion luminescence of Yb3+/Ln3+ (Ln=Ho, Er, Tm) co-doped Y2Ti2O7 ceramics

Y2Ti2O7:Yb3+/Ln(3+) (Ln = Ho, Er, Tm) translucent ceramics were successfully fabricated by sintering method using synthetic nano-sized Y2Ti2O7:5% Yb3+, 1% Ln(3+) powders for the first time. The effect of pressure and grinding on the microstructure, light transmission of the three ceramics samples was investigated. It was demonstrated that less microscopic flaws (micro-cracks and internal pores) and higher light transmission in the Y2Ti2O7:Yb3+/Ln(3+) ceramics could be obtained by increasing the compacting pressure and powder grinding time. The upconversion luminescence was studied on the Y2Ti2O7:Yb3+/Ho3+, Y2Ti2O7:Yb3+/Er3+ and Y2Ti2O7:Yb3+/Tm3+ ceramics pumped by a 980 nm diode laser, intense green, yellow and blue upconversion emissions were observed, respectively. The dependence of upconversion emission intensity on the excitation power was examined, and the possible upconversion mechanisms had been proposed accordingly. (C) 2015 Elsevier Ltd. All rights reserved.