title: Effect of Tm³⁺ Concentration and Temperature on Blue and NIR Upconversion Luminescence in Tm³⁺/Yb³⁺ Co-Doped NaY(WO₄)₂ Microstructures.
abstract: Tm³⁺/Yb³⁺ codoped NaY(WO₄)₂ microstructures with various Tm³⁺ concentrations and 10 mol% Yb³⁺ concentration were prepared by a microwave-assisted hydrothermal method, and their upconversion luminescence (UCL) was investigated. Under excitation at 980 nm, Tm³⁺/Yb³⁺ codoped NaY(WO₄)₂ exhibited strong blue and near infrared (NIR) emissions, respectively, corresponding to ¹G₄ --> ³H₆ and ³H₄ --> ³H₆ transitions, with weak red emission due to the ¹G₄ --> ³H₄ transition. The optimum doping concentrations of Tm³⁺ for the highest blue and NIR UCL were investigated, and it was found that the optimal concentrations for blue and NIR emissions were 0.5 mol% and 1.5 mol%, respectively. In addition, an analysis of temperature dependent blue and NIR UCL in both the samples with low and high Tm³⁺ concentrations, respectively, was undertaken. The results implied that the sample with low Tm³⁺ concentration displayed more obvious effect on the thermal quenching of ¹G₄ level.
authors.forename: Suyuan
authors.initials: S
authors.lastname: Xiang
authors.forename: Hui
authors.initials: H
authors.lastname: Zheng
authors.forename: Yanqiu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Tianxiang
authors.initials: T
authors.lastname: Peng
authors.forename: Xiangqing
authors.initials: X
authors.lastname: Zhang
authors.forename: Baojiu
authors.initials: B
authors.lastname: Chen