Investigação das propriedades ópticas de nanocristais de Perovskita – CsPbI3 crescidos em matriz vítrea, dopados com íons de Neodímio - Nd3+

• Ano de defesa: 2023
• Autor(a) principal: Ferreira, Davi Ladislau
• Orientador(a): Silva, Ricardo Souza da
• Banca de defesa: Condeles, José Fernando , Oliveira, João Batista de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• dARK ID: ark:/80033/00130000025xb
• Idioma: por
• Instituição de defesa: Universidade Federal do Triângulo Mineiro
• Programa de Pós-Graduação: Programa de Pós-graduação em Ciências e Tecnologia dos Materiais
• Departamento: Universidade Federal do Triângulo Mineiro
• País: Brasil
• Palavras-chave em Português: Nanotecnologia; Nanopartículas; Perovskita; Terras-raras; Sistemas Vítreos
• Área do conhecimento CNPq: Engenharias
• Link de acesso: https://deposita.ibict.br/handle/deposita/728

The main objective of this work is to synthesize and characterize the optical, structural and electronic properties of Perovskite - CsPbI3 nanocrystals grown in a glass matrix, doped with Nd3+ ions. The synthesis process of the material was based on the fusion of the reagents in an electric furnace, followed by sudden cooling, in order to control the nucleation and growth rate of the nanocrystals, in addition to being the mechanism for forming the amorphous phase of the matrix, the glass. The material was heat treated in an electric furnace for different times, keeping the temperature constant, in order to verify the influence of the size of the nanocrystals in relation to the quantum confinement of the system. The analysis of the optical properties of the nanocrystals was performed by UVVis-NIR Optical Absorption Spectroscopy, Photoluminescence Spectroscopy and Fluorescence Lifetime Spectroscopy as a function of temperature. The structural characterizations were performed by X-ray Diffraction, Transmission Electron Microscopy and Selected Area Electron Diffraction. As experimental results, the presence of energy transfer from CsPbI3 nanocrystals to Nd3+ ions embedded in glassy systems (SBNAPC: SiO2-B2O3–NaI–Al2O3–PbI2–Cs2CO3) was observed. The radiative and non-radiative energy transfer between the Perovskite nanocrystals and the levels of Nd3+ ions could be observed in the photoluminescence spectra, with the main characteristic being absorption in the ultraviolet region and emission in the visible region. The results obtained demonstrate the presence of nanocrystals with a predominant orthorhombic structure, with cubic structures being found in some regions. These nanocrystals have an average size of 7 nm, which indicates the presence of high quantum confinement of the system. It is believed that these results may inspire further investigation of similar systems to enable the development of possible devices or laser applications. In addition, the synthesis strategy in a glass matrix has proven to be effective in protecting nanocrystals from chemical attack in a hostile environment, ensuring long-term stability, when compared to the colloidal system, since these are easily oxidized or inactivated in the presence of oxygen, humidity or light irradiation.