Understanding the origin of photoluminescence in disordered Ca0.60Sr0.40WO4: An experimental and first-principles study
| Autor: | Elson Longo, S. L. Porto, Valeria M. Longo, José Arana Varela, J. W. M. Espinosa, Laécio S. Cavalcante, Emmanuelle Orhan |
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| Přispěvatelé: | Departamento de Quinica Departamento de Fisica, Universidade Federal de Sao Carlos, Axe 3 : organisation structurale multiéchelle des matériaux, Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), CCEN Departamento de Quimica, Universidade Federal da Paraiba (UFPB), Instituto de Quimica, Universidade Estadual Paulista Júlio de Mesquita Filho = São Paulo State University (UNESP)-Instituto de Quinica |
| Rok vydání: | 2007 |
| Předmět: |
Photoluminescence
Condensed matter physics Chemistry General Physics and Astronomy Charge (physics) 02 engineering and technology Electron Electronic structure 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Condensed Matter::Materials Science Ab initio quantum chemistry methods Optical materials Density of states Cluster (physics) Density functional theory Ab initio calculations CSW Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Chemical Physics Chemical Physics, Elsevier, 2007, 334, pp.180-188. ⟨10.1016/j.chemphys.2007.02.025⟩ |
| ISSN: | 0301-0104 |
| DOI: | 10.1016/j.chemphys.2007.02.025 |
| Popis: | International audience; Visible photoluminescence (PL) was observed for the first time at room temperature in structurally disordered calcium strontium tungstate powder, Ca0.60Sr0.40WO4 (CSW), obtained by the polymeric precursor method. The PL behavior of CSW powders has been analyzed as a function of the disorder rate, based on experimental and theoretical studies. Quantum mechanical theory based on density functional theory at the B3LYP level has been employed to study the electronic structure of two periodic models representing both crystalline and disordered powders. Their electronic structures have been analyzed in terms of density of states, band dispersion and charge densities. The calculations indicate a break in symmetry when passing from crystalline to disordered models, creating localized electronic levels above the valence band. Moreover, a negative charge transfer process takes place from the [WO3] cluster to the [WO4] cluster. The polarization induced by the break in symmetry and the existence of localized levels favors the creation of trapped holes and electrons, originating the PL phenomenon. |
| Databáze: | OpenAIRE |
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