Systematic Studies on RE2Hf2O7:5%Eu3+ (RE = Y, La, Pr, Gd, Er, and Lu) Nanoparticles: Effects of the A-Site RE3+ Cation and Calcination on Structure and Photoluminescence

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• 作者：Madhab Pokhrel ; Kareem Wahid ; Yuanbing Mao
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：July 14, 2016
• 年：2016
• 卷：120
• 期：27
• 页码：14828-14839
• 全文大小：883K
• 年卷期：0
• ISSN：1932-7455

文摘

A series of 5 mol % Eu³⁺-doped rare earth (RE) hafnium oxide RE₂Hf₂O₇ (RE = Y, La, Pr, Gd, Er, and Lu) nanoparticles (NPs) have been synthesized, calcinated, and systematically investigated using X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and optically excited luminescence. Effects of the A-site RE³⁺ cation and calcination on the crystal structure of the RE₂Hf₂O₇:5%Eu NPs were distinguished using XRD and Raman studies. Spectroscopic analysis showed that the La₂Hf₂O₇:5%Eu³⁺ and Pr₂Hf₂O₇:5%Eu³⁺ possessed ordered pyrochlore structures while the RE₂Hf₂O₇:5%Eu³⁺ compositions (RE = Y, Er, and Lu) possessed disordered fluorite structure and were thermodynamically stable up to the highest calcination temperature employed in this study (1500 °C); however, a disordered–ordered transition observed in the Gd₂Hf₂O₇:5%Eu³⁺ composition indicated that it was not thermodynamically stable. Detailed photoluminescence (PL) studies, including quantum yield and decay properties of each sample before and after calcination, were performed and correlated with their compositions and crystal structures. These results suggest that the A site RE³⁺ cations and calcination of these RE₂Hf₂O₇:5%Eu NPs play important roles in their PL properties.