Estudo de nanomateriais híbridos à base de óxido de grafeno e nanocristais semicondutores

• Ano de defesa: 2022
• Autor(a) principal: Nascimento, Rosinildo Fideles do
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Uberlândia; Brasil; Programa de Pós-graduação em Física
• Palavras-chave em Português: Pontos quânticos ultrapequenos; CdSe/CdS; Nanocompósitos; Propriedades ópticas; Propriedades elétricas; Óxido de grafeno reduzido; Propriedades estruturais; Propriedades vibracionais; Propriedades morfológicas; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA; Física; Materiais nanoestruturados; Grafita; Semicondutores complementares de óxido metálico
• Link de acesso: https://repositorio.ufu.br/handle/123456789/36180; http://doi.org/10.14393/ufu.te.2022.5023

In this study, reduced graphene oxide (rGO) was successfully synthesized and covalently conjugated to ultra-small quantum dots (USQDs) forming the core/shell of CdSe/CdS a nanocomposite. The technical and vibrational properties of the protocol were investigated using X-ray Diffraction (XRD), Raman Spectroscopy (ER) and Fourier Transform Infrared Spectroscopy (FTIR). The confirmation of conjugation and the influence of the concentration of USQDs were investigated by FTIR, High Resolution Transmission Electron Microscopy (HRTEM), Fluorescence (FL), Time-Resolved Luminescence (PL-RT) and Cyclic Voltammetry (VC) techniques. XRD diagrams observed some characteristic diffraction peaks of graphite oxide and a small amount of graphite. In the Raman spectra, the appearance of the band was observed and the formation of a GO was observed. In the FTIR spectra, the characteristics of functional and post-carboxylic groups were observed, confirming the agreement of grahydroxyl and excellent agreement with the Raman XRD data. The link between the hydroxyl groups of the USQDs and the carboxylic groups of the rGO was confirmed by the FTIR results. In the associations, also in the hydroxyl epoxy and hydroxyl groups. HRTEM images guarantee FTIR results. The payload nanocomposites display associates a luminescence display with concentration of USQDs, a download displayed for payload USQDs from the USQGOs. In the PL-RT spectra it was observed that a non-radiative decay rate is due to the electron transfer process, owing to the lifetime. VC experiments confirmed that with increasing concentration of USQD there was an increase in the conductivity of nanocomposites. Therefore, we demonstrate that it is possible to tune the optical and electrical properties of rGO-CdSe/CdS nanocomposites as a function of the concentration of USQDs.