Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/124957
Title: A joint experimental and theoretical study on the electronic structure and photoluminescence properties of Al2(WO4)3 powders
Author: Costa Batista, Francisco Marcos
La Porta, Felipe A.
Gracia, Lourdes
Cerdeiras Montero, Elena
Mestres i Vila, Ma. Lourdes
Siu Li, Máximo
Batista, Nougat Cardoso
Andrés, Juan
Longo, Elson
Cavalcante, Laécio Santos
Keywords: Estructura electrònica
Clústers metàl·lics
Teoria del funcional de densitat
Luminescència
Fotoquímica
Electronic structure
Metal clusters
Density functionals
Luminescence
Photochemistry
Issue Date: 5-Feb-2015
Publisher: Elsevier B.V.
Abstract: In this paper, aluminum tungstate Al2(WO4)3 powders were synthesized using the co-precipitation method at room temperature and then submitted to heat treatment processes at different temperatures (100, 200, 400, 800, and 1000 °C) for 2 h. The structure and morphology of the powders were characterized by means of X-ray diffraction (XRD), Rietveld refinement data, and field emission scanning electron microscopy (FE-SEM) images. Their optical properties were examined with ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy and photoluminescence (PL) measurements. XRD patterns and Rietveld refinement data showed that Al2(WO4)3 powders heat treated at 1000 °C for 2 h have a orthorhombic structure with a space group (Pnca) without the presence of deleterious phases. FE-SEM images revealed that these powders are formed by the aggregation of several nanoparticles leading to the growth of microparticles with irregular morphologies and an agglomerated nature. UV-vis spectra indicated that optical band gap energy increased from 3.16 to 3.48 eV) as the processing temperature rose, which was in turn associated with a reduction in intermediary energy levels. First-principle calculations were performed in order to understand the behavior of the PL properties using density functional theory at the B3LYP calculation level on periodic model systems and indicate the presence of stable electronic excited states (singlet). The analyses of the band structures and density of states at both ground and first excited electronic states provide insight into the main features, based on structural and electronic order-disorder effects in octahedral [AlO6] clusters and tetrahedral [WO4] clusters, as constituent building units of this material.
Note: Versió postprint del document publicat a: https://doi.org/10.1016/j.molstruc.2014.10.016
It is part of: Journal of Molecular Structure, 2015, vol. 1081, p. 381-388
URI: http://hdl.handle.net/2445/124957
Related resource: https://doi.org/10.1016/j.molstruc.2014.10.016
ISSN: 0022-2860
Appears in Collections:Articles publicats en revistes (Química Inorgànica i Orgànica)

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