Structural, morphological and optical properties of Ca10V6O25

• Ano de defesa: 2020
• Autor(a) principal: Teixeira, Mayara Mondego
• Orientador(a): Silva, Elson Longo da
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de São Carlos; Câmpus São Carlos
• Programa de Pós-Graduação: Programa de Pós-Graduação em Química - PPGQ
• Palavras-chave em Inglês: Calcium vanadate Ca10V6O25; White emission; Thermal quenching; Optical properties; Density Functional Theory
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/12996

Modeling the structure and morphology of crystals is of great interest in the field of science and industry, as these factors are strongly linked in determining the properties of materials. That said, Ca10V6O25 compounds were synthesized by the coprecipitation and the microwave-assisted hydrothermal methods in a different time and temperature conditions in order to optimize their photoluminescent property. These methods were efficient to obtain different morphologies, in addition, the effect of the synthesis conditions had a strong influence on the microstructure and optical properties of vanadium compounds. Then a growth mechanism was proposed for the different particles formed, and it was observed that the synthesis method has a strong influence on the degree of structural order/disorder. By controlling the morphology and types of defects in the crystal lattice, different emission colors can be observed for the Ca10V6O25 compounds. Since, the sample that presented a balance in the degree of order/disorder structural in the short-, medium-, long-range, exhibited an emission in the white region by the coordinates of the CIE chromaticity diagram. Then, the luminescence mechanism for the synthesized compounds was proposed, as well as its structure and electronic properties were revealed through the relationship between theoretical calculation and experimental data. The photoluminescent property was investigated in detail which was observed that in addition to the electronic transition typical of the [VO4] clusters, there is the contribution of energy levels that are located within the band gap. These energy levels were formed by different types of disorder at short-, medium-, and long-range in the structure.