Microwave hydrothermal synthesis and temperature sensing behavior of Lu2Ti2O7:Yb3þ/Er3þ nanophosphors

다국어 초록 (Multilingual Abstract)

Lu2Ti2O7:Yb3þ/Er3þ (LTO:Yb3þ/Er3þ) nanophosphors codoped with Yb3þ (8e20 at%) and Er3þ ions (0.5 e4 at%) were synthesized by a microwave hydrothermal process. Under the 980 nm excitation, the sample gives a set of upconversion light: very strong red emissions near 661 nm (4F9/2 / 4I15/2), weak green around 523 nm and 545 nm (2H11/2/4I15/2 and 4S3/2/4I15/2, respectively). The optimum doping concentrations of Er3þ and Yb3þ for the highest emission intensity were determined by photoluminescence (PL) analyses. Concentration dependent studies revealed that the optimal composition was realized for the 12 at% Yb3þ and 2.0 at% Er3þ-doping concentration with a strong emission. A possible UC mechanism for LTO:Yb3þ/Er3þ is discussed via the change of the pump power. The temperature dependence of the fluorescence intensity ratios (FIR) for the two green UC emission bands peaked at 523 and 545 nm was studied in the range of 298e573 K under excitation by a 980 nm diode laser and the maximum sensitivity was approximately 0.00313 K『1 at 536 K. This indicates that LTO:Yb3þ/Er3þ nanophosphors are potential candidates for optical temperature sensors with high sensitivity.

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