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

作者：Cavalcante L S^*; Moraes E; Almeida M A P; Dalmaschio C J; Batista N C; Varela J A; Longo E; Li M Siu; Andres J; Beltran A

来源：Polyhedron, 2013, 54: 13-25.

DOI：10.1016/j.poly.2013.02.006

• ZnMoO4
• Raman
• Defects
• Band gap
• DFT
• Photoluminescence

In this paper, a combined theoretical and experimental study on the electronic structure and photoluminescence (PL) properties of beta zinc molybdate (beta-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 (FTIR) 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 beta-ZnMoO4 crystals are (O 2p-valence band and Mo 4d-conduction band). Finally, PL properties of beta-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.

• 出版日期2013-4-30