Mechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states
Scholar | Otros documentos del autor: Carvalho Oliveira, Marisa; Gracia Edo, Lourdes; Assis, Marcelo de; Viana Rosa, Ieda Lucía; Do Carmo Gurgel, Maria Fernanda; Longo, Elson; Andrés, Juan
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TítuloMechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states
Fecha de publicación2017-10
Versión del editorhttp://www.sciencedirect.com/science/article/pii/S0925838817320285
CaZrO3 (CZO) powders obtained by the polymeric precursor method at 400 °C, and then, the samples were annealed at different temperatures (400, 600, 800, and 1000 °C) and characterized by X-ray diffraction, Raman and ... [+]
CaZrO3 (CZO) powders obtained by the polymeric precursor method at 400 °C, and then, the samples were annealed at different temperatures (400, 600, 800, and 1000 °C) and characterized by X-ray diffraction, Raman and ultraviolet–visible spectroscopic methods, along with photoluminescence (PL) emissions. First principle calculations based on the density functional theory (DFT), using a periodic cell models, provide a theoretical framework for understanding the PL spectra based on the localization and characterization of the ground and electronic excited states. Fundamental (singlet, s) and excited (singlet, s*, and triplet, t*) electronic states were localized and characterized using the ideal and distorted structures of CZO. Their corresponding geometries, electronic structures, and vibrational frequencies were obtained. A relationship between the different morphologies and structural behavior has also been established. Polarized structures were identified by the redistribution of the 4dz2, 4dyz, and 4dxy (Zr) orbitals at the conduction band and the 2pz (O) orbital in the valence band for s, s* and t*. Analysis of the vibrational eigenvector modes of these electronic states reveals a relationship between them via asymmetric bending and stretching modes that arise from Zr atom displacements due to polyhedral [ZrO6] distortion. Furthermore, the results provided an insight into the PL emissions of the as-synthesized CaZrO3 and led to the conclusion that the presence of electronically excited states is strongly related to the structural order-disorder effects (polyhedral distortion) at short range for both [ZrO6] and [CaO8] clusters. [-]
Palabras clave / Materias
Proyecto de investigaciónGeneralitat Valenciana (PrometeoII/2014/022 and ACOMP/2014/270, ACOMP/2015/1202) ; Ministerio de Economía y Competitividad (project CTQ2015-65207-P) ; Ministerio de Educación. Programa de Cooperación Cientifíca con Iberoamerica (Brasil) (PHBP14-00020) ; Ministerio de Economia y Competitividad (“Salvador Madariaga” program, PRX15/00261) ; Generalitat Valencia (Santiago Grisolia program 2015/033)
Cita bibliográficaOLIVEIRA, Marisa Carvalho, et al. Mechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states. Journal of Alloys and Compounds, 2017, vol. 722, p. 981-995.
Tipo de documentoinfo:eu-repo/semantics/article
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