Síntese e caracterização de silicato de zinco dopado com manganês
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Data
2019-08-19
Autores
Porcel, Henrique Reatto [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Os materiais nanoestruturados vêm sendo extensivamente estudados, não somente pelas novas propriedades e suas possíveis aplicações tecnológicas, mas também pela busca de uma melhor compreensão dos aspectos físicos e químicos. Em relação a materiais semicondutores, estudos da estrutura em escala nanométrica tem recebido considerável interesse em razão do efeito de tamanho que exibem. Semicondutores nanocristalinos apresentam propriedades eletrônicas intermediárias entre aqueles de estrutura molecular e sólidos macrocristalinos e são objeto de intensa pesquisa, apresentando uma grande diversidade de aplicações quando na forma nanoestruturada. Dentre esses materiais, o silicato de zinco (Zn2SiO4) puro ou dopado tem recebido atenção em razão de notáveis propriedades fundamentais, versatilidade e potencial para diversas aplicações tecnológicas. Nesse contexto, essa dissertação teve como objetivo realizar a síntese e a caracterização de Zn2SiO4 puro e dopado com átomos de manganês e sua correlação com propriedades fotoluminescentes. Neste trabalho, foi utilizado o método químico de preparação conhecido por co-preciptação. Deste modo, a caracterização morfológica foi realizada através da técnica de microscopia eletrônica de varredura de alta resolução (FEG-MEV), a qual demonstra um aglomerado de grãos, tornando a determinação do tamanho do mesmo difícil. As propriedades estruturais das nanopartículas, bem como suas propriedades físicas e químicas, foram determinadas através das técnicas de difração de raios X, espectroscopia Raman e fotoluminescência, com a qual é possível observar a formação de partículas nanométricas e os picos de excitação e emissão. A estrutura local dos materiais semicondutores foi avaliada através de técnicas absorção de raios X (XANES) as quais foram realizadas no Laboratório Nacional de Luz Sincrotron (LNLS), onde foram analisadas a borda K do Mn.
Nanostructured materials have been extensively studied, not only for new properties and their possible technological applications, but also for a better understanding of the physical and chemical aspects. With regard to semiconductor materials, nanoscale structure studies have received considerable interest because of the size effect they exhibit. Nanocrystalline semiconductors have intermediate electronic properties between those of molecular structure and macrocrystalline solids and are the subject of intense research, presenting a great diversity of applications when in nanostructured form. Among these materials, pure or doped zinc silicate (Zn2SiO4) has received attention because of its remarkable fundamental properties, versatility and potential for various technological applications. In this context, this dissertation aimed to synthesize and characterize pure and doped Zn2SiO4 with manganese atoms and its correlation with photoluminescent properties. In this work, the chemical preparation method known as co-precipitation was used. Thus, the morphological characterization was performed by the high resolution scanning electron microscopy (FEG-SEM) technique, which demonstrates a grain cluster, making the size determination difficult. The structural properties of nanoparticles, as well as their physical and chemical properties, were determined by X-ray diffraction, Raman spectroscopy and photoluminescence techniques, with which it is possible to observe the formation of nanometric particles and the excitation and emission peaks. The local structure of the semiconductor materials was evaluated by X-ray absorption techniques (XANES) which were performed at the Sincrotron National Light Laboratory (LNLS), where the Mn K edge was analyzed.
Nanostructured materials have been extensively studied, not only for new properties and their possible technological applications, but also for a better understanding of the physical and chemical aspects. With regard to semiconductor materials, nanoscale structure studies have received considerable interest because of the size effect they exhibit. Nanocrystalline semiconductors have intermediate electronic properties between those of molecular structure and macrocrystalline solids and are the subject of intense research, presenting a great diversity of applications when in nanostructured form. Among these materials, pure or doped zinc silicate (Zn2SiO4) has received attention because of its remarkable fundamental properties, versatility and potential for various technological applications. In this context, this dissertation aimed to synthesize and characterize pure and doped Zn2SiO4 with manganese atoms and its correlation with photoluminescent properties. In this work, the chemical preparation method known as co-precipitation was used. Thus, the morphological characterization was performed by the high resolution scanning electron microscopy (FEG-SEM) technique, which demonstrates a grain cluster, making the size determination difficult. The structural properties of nanoparticles, as well as their physical and chemical properties, were determined by X-ray diffraction, Raman spectroscopy and photoluminescence techniques, with which it is possible to observe the formation of nanometric particles and the excitation and emission peaks. The local structure of the semiconductor materials was evaluated by X-ray absorption techniques (XANES) which were performed at the Sincrotron National Light Laboratory (LNLS), where the Mn K edge was analyzed.
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Palavras-chave
Física aplicada, Silicato de zinco, Nanopartículas, Difração de raios X, Applied physics, Zinc silicate, Nanoparticles, X-ray diffraction, Silicato, Zn2SiO4, Silicate