Size and Concentration Effects on the Photoluminescence of La2O2S:Eu3+ Nanocrystals

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• 作者：Qilin Dai ; Hongwei Song ; Meiyuan Wang ; 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：19399-19404
• 全文大小：196K
• 年卷期：v.112,no.49(December 11, 2008)
• ISSN：1932-7455

文摘

The effects of size and europium concentration on photoluminescence properties of La₂O₂S: Eu³⁺ nanocrystals (20 nm) and the corresponding bulk were studied. The results indicate that in nanocrystals, the absorption edge largely shifted to blue in comparison to the bulk, which was mainly attributed to the variation of phonon-excitation relaxation. Two excitation bands were observed, located at 250 and 330 nm, respectively, corresponding to the charge transfer (CT) transitions of Eu−O and Eu−S. Relative to the CT transition of Eu−O, that of Eu−S increased greatly with europium concentration. The dependence of photoluminescence intensity on concentration showed that in the nanocrystals and the bulk, Eu³⁺ ions had two different quenching mechanisms, respectively, the exchange interaction and electric dipole−dipole interaction.