Estrutura e fotoluminescência do germanato de magnésio contendo manganês tetravalente como cátion ativador
DOI:
https://doi.org/10.63595/vetor.v35i1.18365Palavras-chave:
Cerâmicas, Difração de raios-X, Fotoluminescência, Mn4+Resumo
Apresentamos a síntese pelo método do acetato do composto germanato de magnésio (Mg2GeO4) contendo Mn4+ como cátion ativador de transições ópticas. A estrutura cristalina do composto foi caracterizada através de medidas de difração de raios-X em conjunto com o método de Rietveld, que confirmaram a formação do composto pretendido. Medidas de espectroscopia de fotoluminescência mostram uma emissão na região do vermelho. Sob excitação de 287 nm, o espectro de emissão exibe um pico intenso em 660 nm, acompanhado de diversas estruturas. As transições ópticas foram identificadas e confirmam a ocupação do Mn4+ em simetria octaédrica. A partir dos espectros ópticos os parâmetros de campo cristalino Dq, B e C foram calculados. O tempo de vida da emissão é da ordem de 2,8 ms, compatível com a transição eletrônica proibida por spin 2E(2G) → 4A2(4F) atribuída à emissão em 660 nm. Os resultados indicam que a amostra foi sintetizada com sucesso e as suas propriedades ópticas podem ser aproveitadas em dispositivos que operam com emissão na faixa do vermelho no espectro visível.
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