Theoretical investigation on the optical and EPR spectra for Cu2+‐doped ZnO‐CdS nanocomposites
Theoretical investigation on the optical and EPR spectra for Cu2+‐doped ZnO‐CdS nanocomposites
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DOI：
10.1002/mrc.4813
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发表时间：
2019-01
影响因子：
2
通讯作者：
H. Zhang;Chao-chao Yan;Q. Zhu
中科院分区：
文献类型：
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作者：
H. Zhang;Chao-chao Yan;Q. Zhu
从基于团簇理论的微扰公式出发，对ZnO-CdS复合纳米粉体中[CuO 6]10−心的三个光吸收带和EPR参量进行了理论研究.在公式中，考虑了配体轨道和自旋-轨道耦合作用通过共价效应对EPR参量的贡献。对于所研究的[CuO 6]10−簇合物，由于Jahn-Teller效应，Cu-O键长沿z-轴显示出相对伸长比ρ（沿着4.1%）。这项工作中提出的缺陷模型与之前的假设不同，即当杂质Cu 2+进入Al 2 O3纳米晶体和Al 2 O3纳米晶体的晶格时，它可以取代宿主Zn 2+的位置，形成四面体[Cu Al 2 O3 4]6−簇（Al 2 O3 = O，S）。最后对模型的有效性进行了讨论。本计算和以前的ZnO纳米晶体的间隙Cu 2+中心之间的差异进行了分析，鉴于不同的杂质行为，由于新的组合物CdS和不同的制备条件。
The three optical absorption bands and EPR parameters of the [CuO6]10− center in the ZnO‐CdS composite nanopowders are theoretically studied from the perturbation formulas based on the cluster approach. In the formulas, the contributions to EPR parameters arising from the ligand orbital and spin–orbit coupling interactions via covalence effect are considered. For the studied [CuO6]10− cluster, the Cu–O bond lengths are suggested to show a relative elongation ratio ρ (≈ 4.1%) along the z‐axis due to Jahn–Teller effect. The defect models suggested in this work are different from the previous assumption that the impurity Cu2+ can replace the host Zn2+ site when it enters the lattices of the ΖnO and ΖnS nanocrystals, forming the tetrahedral [CuΧ4]6− clusters (Χ = O, S). The validity of the proposed model is discussed. The differences between the present calculations and the previous ones for the interstitial Cu2+ center in ZnO nanocrystals are analyzed in view of the dissimilar impurity behaviors due to the new composition CdS and distinct preparation conditions.