Ce–O Covalence in Silicate Oxyapatites and Its Influence on Luminescence Dynamics
Ce–O Covalence in Silicate Oxyapatites and Its Influence on Luminescence Dynamics
复制标题
DOI：
10.1021/jp5049293
复制
发表时间：
2014-07
影响因子：
3.7
通讯作者：
Dengyun Zhai;Lixin Ning;Yucheng Huang;Guokui Liu
中科院分区：
文献类型：
--
作者：
Dengyun Zhai;Lixin Ning;Yucheng Huang;Guokui Liu
在Ca_2Gd_8（SiO_4）_6O_2中，铈取代钆占据了两个不同配位的本征位置。在同一晶体化合物中，在4F位点处的离子键合和在6 H位点处的离子-共价混合键合的共存为离子-配体相互作用的比较研究提供了理想的系统。在实验上，研究了这种白色荧光粉的光谱特性和光致发光动力学。分析了Ce ~（3+）在6 H位的光致发光的异常热猝灭现象。理论上，从头计算进行揭示的独特性质的Ce-O配位在两个Ce 3+网站。计算的Ce ~（3+）在6 H位的本征态表明，Ce ~（3+）与其中一个未与Si ~（4+）键合的配位氧离子形成了弱的Ce-O共价键。的电子能级和频率的本地振动模式与特定的Ce-O对提供一个比较理解的网站分辨的实验结果。吧...
Cerium substituting gadolinium in Ca2Gd8(SiO4)6O2 occupies two intrinsic sites of distinct coordination. The coexistence of an ionic bonding at a 4F site and an ionic–covalent mixed bonding at a 6H site in the same crystalline compound provides an ideal system for comparative studies of ion–ligand interactions. Experimentally, the spectroscopic properties and photoluminescence dynamics of this white-phosphor are investigated. An anomalous thermal quenching of the photoluminescence of Ce3+ at the 6H site is analyzed. Theoretically, ab initio calculations are conducted to reveal the distinctive properties of the Ce–O coordination at the two Ce3+ sites. The calculated eigenstates of Ce3+ at the 6H site suggest a weak Ce–O covalent bond formed between Ce3+ and one of the coordinated oxygen ions not bonded with Si4+. The electronic energy levels and frequencies of local vibrational modes are correlated with specific Ce–O pairs to provide a comparative understanding of the site-resolved experimental results. On...