Structure and Upconversion Luminescence of Hydrothermal PbWO4:Er3+, Yb3+ Powders

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• 作者：Qilin Dai ; Hongwei Song ; Xinguang Ren ; Shaozhe Lu ; Guohui Pan ; Xue Bai ; Biao Dong ; Ruifei Qin ; Xuesong Qu ; Hui Zhang
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：December 11, 2008
• 年：2008
• 卷：112
• 期：49
• 页码：19694-19698
• 全文大小：182K
• 年卷期：v.112,no.49(December 11, 2008)
• ISSN：1932-7455

文摘

PbWO₄: Er³⁺,Yb³⁺ nanocrystals (100 nm) were prepared by the hydrothermal method at different pH values (pH = 4, 7, and 9). Their structure and luminescence properties under 978-nm laser-diode excitation were studied. The results indicate that the practical ratio of W to Pb in the nanocrystals and the doping concentration of Yb³⁺ depended strongly on the pH value due to structure change. In upconversion, red (⁴F_9/2→⁴I_15/2) and green (²H_11/2,⁴S_3/2→⁴I_15/2) emissions were observed, both of which occurred via a two-photon populating process. Biexponential upconversion dynamics were observed, which was attributed to luminescence centers surrounded by different local environments. The intensity ratio of ²H_11/2→⁴I_15/2 to⁴S_3/2→⁴I_15/2 (R_HS) was explored to reveal the local thermal effect under the exposure of the laser diode, showing that the temperature at the exposed spot increased linearly with respect to excitation power density and Yb³⁺ concentration.