Síntese e caracterização de materiais nanoestruturados luminescentes à base de CaAl2O4

• Autor(a) principal: Silva, Gabriela Maria Rodrigues da [UNESP]
• Data de Publicação: 2018
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/203686; http://www.athena.biblioteca.unesp.br/exlibris/bd/capelo/2019-06-17/000916662.pdf
• topic: Materiais nanoestruturados; Nanoestrutura; Luminescencia; Fotoluminescencia; Nanopartículas

Nanostructured materials have been extensively studied, not only for the new properties and their possible technological applications, but also for the search for a better understanding of the physical and chemical aspects that cause such changes. Among these materials, pure or doped calcium aluminate (CaAl2O4) has received attention due to remarkable fundamental properties, versatility and potential for several technological applications. However, there is no consensus in the literature regarding the nature of the emission of photoluminescence in these nanocrystalline materials. CaAl2O4 doped with rare earths or transition metals showed interesting luminescent properties and has since been investigated as a possible host material for long-lasting persistent phosphors. In this context, this work aims to perform the synthesis and characterization of CaAl2O4 pure or doped with Mn and Ce atoms and to correlate the photoluminescent properties with structure characterization. In this work, chemical preparation methods were used, such as the polymer precursor method. The morphological characterization was done through techniques such as high-resolution scanning electron microscopy (FEG-MEV). The structural properties of nanoparticles, as well as their physical and chemical properties, were determined by conventional techniques such as X-ray diffraction, Raman spectroscopy, electron paramagnetic resonance (EPR) and photoluminescence. The results obtained from the above cited techniques showed that the CaAl2O4:Ce and CaAl2O4:Mn samples were successfully prepared by the polymer precursor method. The results of the X-ray diffraction showed that at 1100 °C there is no spurious phase formation for the CaAl2O4:Mn samples whereas for the CaAl2O4:Ce samples the second phase formation is observed. The results of Raman spectroscopy confirm the formation of the P121/n1 space group monoclinic phase and also evidence the presence of CeO2 secreted in the...