Theoretical investigation on the optical and EPR spectra for Cu 2+ ‐doped ZnO‐CdS nanocomposites

Abstract The three optical absorption bands and EPR parameters of the [CuO 6 ] 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...

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Published in:Magnetic resonance in chemistry 2019-02, Vol.57 (2-3), p.144-148
Main Authors: Zhang, H.M., Yan, C., Zhu, Q.S.
Format: Article
Language:English
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Summary:Abstract The three optical absorption bands and EPR parameters of the [CuO 6 ] 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 [CuO 6 ] 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 Cu 2+ can replace the host Zn 2+ site when it enters the lattices of the ΖnO and ΖnS nanocrystals, forming the tetrahedral [CuΧ 4 ] 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 Cu 2+ center in ZnO nanocrystals are analyzed in view of the dissimilar impurity behaviors due to the new composition CdS and distinct preparation conditions.
ISSN:0749-1581
1097-458X
DOI:10.1002/mrc.4813