A combined theoretical and experimental study of electronic structure and optical properties of ¦Â-ZnMoO₄ microcrystals

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• 作者：L.S. Cavalcante^a ; ^b ; ^{laeciosc@bol.com.br} ; E. Moraes^c ; M.A.P. Almeida^c ; C.J. Dalmaschio^c ; N.C. Batista^b ; J.A. Varela^a ; E. Longo^a ; M. Siu Li^d ; J. André ; s^e ; A. Beltrá ; n^e
• 关键词：ZnMoO4 ; Raman ; Defects ; Band gap ; DFT ; Photoluminescence
• 刊名：Polyhedron
• 出版年：2013
• 出版时间：30 April, 2013
• 年：2013
• 卷：54
• 期：Complete
• 页码：13-25
• 全文大小：2932 K

文摘

In this paper, a combined theoretical and experimental study on the electronic structure and photoluminescence (PL) properties of beta zinc molybdate (¦Â-ZnMoO₄) microcrystals synthesized by the hydrothermal method has been employed. These crystals were structurally characterized by X-ray diffraction (XRD), Rietveld refinement, Fourier transform Raman (FT-Raman) and Fourier transform infrared (FT-IR) spectroscopies. Their optical properties were investigated by ultraviolet-visible (UV-Vis) absorption spectroscopy and PL measurements. First-principles quantum mechanical calculations based on the density functional theory at the B3LYP level have been carried out. XRD patterns, Rietveld refinement, FT-Raman and FT-IR spectra showed that these crystals have a wolframite-type monoclinic structure. The Raman and IR frequencies experimental results are in reasonable agreement with theoretically calculated results. UV-Vis absorption measurements shows an optical band gap value of 3.17 eV, while the calculated band structure has a value of 3.22 eV. The density of states indicate that the main orbitals involved in the electronic structure of ¦Â-ZnMoO₄ crystals are (O 2p-valence band and Mo 4d-conduction band). Finally, PL properties of ¦Â-ZnMoO₄ crystals are explained by means of distortions effects in octahedral [ZnO₆] and [MoO₆] clusters and inhomogeneous electronic distribution into the lattice with the electron density map.