Size and Concentration Effects on the Photoluminescence of La2O2S:Eu3+ Nanocrystals
Size and Concentration Effects on the Photoluminescence of La2O2S:Eu3+ Nanocrystals
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尺寸和浓度对 La2O2S:Eu3 纳米晶体光致发光的影响
DOI：
10.1021/jp808343f
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发表时间：
2008-12-11
影响因子：
3.7
通讯作者：
Zhang, Hui
中科院分区：
文献类型：
--
作者：
Dai, Qilin;Song, Hongwei;Zhang, Hui
研究了La 2 O2 S：Eu 3+纳米晶（约20 nm）及相应体材料的尺寸和Eu浓度对其光致发光性能的影响。结果表明，纳米晶体的吸收边较体材料明显蓝移，这主要归因于声子激发弛豫的变化。观察到两个激发带，分别位于近似250和近似330 nm处，对应于Eu-O和Eu-S的电荷转移（CT）跃迁。相对于Eu-O的CT跃迁，Eu-S的CT跃迁随铕浓度的增加而显著增加。荧光强度与浓度的关系表明，Eu 3+离子在纳米晶和块体中存在两种不同的猝灭机制，分别为交换相互作用和电偶极-偶极相互作用。
The effects of size and europium concentration on photoluminescence properties of La2O2S: Eu3+ nanocrystals (similar to 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 similar to 250 and similar to 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.