Sínteses e caracterizações de nanocristais de óxido de zinco
Ano de defesa: | 2015 |
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Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | , |
Tipo de documento: | Dissertação |
Tipo de acesso: | Acesso aberto |
Idioma: | por |
Instituição de defesa: |
Universidade Federal de Uberlândia
|
Programa de Pós-Graduação: |
Programa de Pós-graduação em Física
|
Departamento: |
Ciências Exatas e da Terra
|
País: |
BR
|
Palavras-chave em Português: | |
Palavras-chave em Inglês: | |
Área do conhecimento CNPq: | |
Link de acesso: | https://repositorio.ufu.br/handle/123456789/15673 https://doi.org/10.14393/ufu.di.2015.89 |
Resumo: | In this work, Zinc oxide (ZnO) nanocrystals (NCs) were synthesized by chemical precipitation method by way of aqueous solution, adopting three synthesis temperatures (0°C, 25°C, and 100°C). After, the samples were annealed at 250°C, 500°C, and 750°C, for two hours. In order to study the effects of synthesis and annealing temperatures in the thermal, structural, morphological, and optical properties of these NCs were performed following characterizations: Differential thermal analysis (DTA), X-ray diffraction (XRD), Raman spectroscopy (Raman), scanning electron microscopy (SEM), optical absorption (OA), and fluorescence (FL). The DTA thermograms gave evidence that both the synthesis temperature as the annealing temperature influenced on the density of Zn(OH)2, crystallinity, density of defects, and morphology of ZnO NCs. The XRD patterns gave strong indications of the majority formation of ZnO NCs with wurtzite structure (JCPDS 36-1451). Next, the Zn(OH)2, in the samples, according to the DTA thermograms, probably was in the amorphous phase. It was found that both the synthesis temperature as the annealing temperature did not change the crystalline structure of the ZnO NCs, however, influenced the crystallinity and the size. The Raman spectra reinforced the results obtained by XRD, with respect to the crystal structure of ZnO NCs, and it was observed that both the synthesis temperature as the heat treatment influenced the degree of disorder and density of oxygen vacancies. It was observed in the SEM pictures that both the synthesis temperature as the annealing temperature changed the morphology and influenced both the size dispersion as the size of the NCs ZnO. The behavior of NCs size is acording with the XRD results. The AO spectra gave indications that the ZnO NCs presented quantum confinement properties, being in agreement with the results of XRD and SEM. The FL spectra reinforced the indications, given from the AO spectra, that the NCs showed quantum confinement properties and that both the synthesis temperature as the annealing temperature influenced the densities of Zn(OH)2, according to the DTA thermograms, and oxygen vacancies, according to the Raman spectra. Moreover, it was possible to establish the relationship between the synthesis and annealing temperatures with the density of energy levels due to various defects in the structure of the NCS. Thus, according to these results, it was possible to control the thermal, structural, morphological, and optical properties of ZnO NCs, synthesized by chemical precipitation method in aqueous solution, from the varying the synthesis and annealing temperatures. It is believed that these results can arouse great interest in scientific research, as the synthesis and processing of ZnO NCs from the methodology adopted in this work, enabling their use in various technological applications. |
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2016-06-22T18:43:13Z2015-03-192016-06-22T18:43:13Z2015-02-23BATISTA, Elisson Andrade. Sínteses e caracterizações de nanocristais de óxido de zinco. 2015. 84 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de Uberlândia, Uberlândia, 2015. Disponível em: https://doi.org/10.14393/ufu.di.2015.89https://repositorio.ufu.br/handle/123456789/15673https://doi.org/10.14393/ufu.di.2015.89In this work, Zinc oxide (ZnO) nanocrystals (NCs) were synthesized by chemical precipitation method by way of aqueous solution, adopting three synthesis temperatures (0°C, 25°C, and 100°C). After, the samples were annealed at 250°C, 500°C, and 750°C, for two hours. In order to study the effects of synthesis and annealing temperatures in the thermal, structural, morphological, and optical properties of these NCs were performed following characterizations: Differential thermal analysis (DTA), X-ray diffraction (XRD), Raman spectroscopy (Raman), scanning electron microscopy (SEM), optical absorption (OA), and fluorescence (FL). The DTA thermograms gave evidence that both the synthesis temperature as the annealing temperature influenced on the density of Zn(OH)2, crystallinity, density of defects, and morphology of ZnO NCs. The XRD patterns gave strong indications of the majority formation of ZnO NCs with wurtzite structure (JCPDS 36-1451). Next, the Zn(OH)2, in the samples, according to the DTA thermograms, probably was in the amorphous phase. It was found that both the synthesis temperature as the annealing temperature did not change the crystalline structure of the ZnO NCs, however, influenced the crystallinity and the size. The Raman spectra reinforced the results obtained by XRD, with respect to the crystal structure of ZnO NCs, and it was observed that both the synthesis temperature as the heat treatment influenced the degree of disorder and density of oxygen vacancies. It was observed in the SEM pictures that both the synthesis temperature as the annealing temperature changed the morphology and influenced both the size dispersion as the size of the NCs ZnO. The behavior of NCs size is acording with the XRD results. The AO spectra gave indications that the ZnO NCs presented quantum confinement properties, being in agreement with the results of XRD and SEM. The FL spectra reinforced the indications, given from the AO spectra, that the NCs showed quantum confinement properties and that both the synthesis temperature as the annealing temperature influenced the densities of Zn(OH)2, according to the DTA thermograms, and oxygen vacancies, according to the Raman spectra. Moreover, it was possible to establish the relationship between the synthesis and annealing temperatures with the density of energy levels due to various defects in the structure of the NCS. Thus, according to these results, it was possible to control the thermal, structural, morphological, and optical properties of ZnO NCs, synthesized by chemical precipitation method in aqueous solution, from the varying the synthesis and annealing temperatures. It is believed that these results can arouse great interest in scientific research, as the synthesis and processing of ZnO NCs from the methodology adopted in this work, enabling their use in various technological applications.Neste trabalho, foram sintetizados nanocristais (NCs) de óxido de zinco (ZnO) pelo método de precipitação química via solução aquosa, adotando três temperaturas de síntese (0°C, 25°C e 100°C). Posteriormente, as amostras foram tratadas termicamente a 250°C, 500°C e 750°C, por duas horas. Com a finalidade de estudar os efeitos das temperaturas de síntese e de tratamento térmico nas propriedades térmicas, estruturais, morfológicas e ópticas desses NCs, foram realizadas as seguintes caracterizações: análise térmica diferencial (DTA), difração de raios-X (DRX), espalhamento Raman (Raman), microscopia eletrônica de varredura (MEV), absorção óptica (AO) e fluorescência (FL). Os termogramas de DTA deram indícios que tanto a temperatura de síntese quanto a de tratamento térmico influenciaram na densidade de Zn(OH)2, cristalinidade, densidade de defeitos e morfologia dos NCs de ZnO. Os difratogramas de DRX deram fortes indícios da formação majoritária de NCs de ZnO com estrutura wurtzita (JCPDS 36-1451). Logo, o Zn(OH)2, presente nas amostras, de acordo com os termogramas de DTA, provavelmente encontra-se na fase amorfa. Verificou-se que tanto a temperatura de síntese quanto a de tratamento térmico não alteraram a estrutura cristalina dos NCs de ZnO, contudo, influenciaram na cristalinidade e no tamanho médio. Os espectros Raman reforçaram os resultados obtidos por DRX, em relação à estrutura cristalina dos NCs de ZnO, e observou-se que tanto a temperatura de síntese quanto a de tratamento térmico influenciaram no grau de desordem e na densidade de vacâncias de oxigênio. Observou-se nas imagens de MEV que tanto a temperatura de síntese quanto a de tratamento térmico alteraram a morfologia e influenciaram tanto na dispersão de tamanhos quanto no tamanho dos NCs de ZnO. O comportamento do tamanho dos NCs está em acordo com os resultados de DRX. Os espectros de AO deram indícios que os NCs de ZnO apresentaram propriedades de confinamento quântico, estando em acordo com os resultados de DRX e MEV. Os espectros de FL reforçaram os inícios, dados a partir dos espectros de AO, que os NCs apresentaram propriedades de confinamento quântico e que tanto a temperatura de síntese quanto a de tratamento térmico influenciaram nas densidades de Zn(OH)2, de acordo com os termogramas de DTA, e de vacâncias de oxigênio, de acordo com os espectros Raman. Além disso, foi possível estabelecer a relação entre as temperaturas de síntese e de tratamento térmico com as densidades dos níveis de energia devido aos vários tipos de defeitos na estrutura dos NCs. Portanto, de acordo com esses resultados, foi possível controlar as propriedades térmicas, estruturais, morfológicas e ópticas dos NCs de ZnO, sintetizados pelo método de precipitação química via solução aquosa, a partir da variação das temperaturas de síntese e de tratamento térmico. Acredita-se que esses resultados possam despertar grande interesse na pesquisa científica, quanto à síntese e processamento de NCs de ZnO a partir da metodologia adotada neste trabalho, possibilitando sua utilização em diversas aplicações tecnológicas.Fundação de Amparo a Pesquisa do Estado de Minas GeraisMestre em Físicaapplication/pdfporUniversidade Federal de UberlândiaPrograma de Pós-graduação em FísicaUFUBRCiências Exatas e da TerraNanocristaisÓxido de zincoPrecipitação químicaSolução aquosaAnálise térmica diferencialDifração de raios-xEspectroscopia RamanMicroscopia eletrônica de varreduraAbsorção ópticaFluorescênciaAnálise térmicaNanocrystalsZinc oxideChemical precipitationAqueous solutionDifferential thermal analysisX-ray diffractionRaman spectroscopyScanning electron microscopyOptical absorptionFluorescenceCNPQ::CIENCIAS EXATAS E DA TERRA::FISICASínteses e caracterizações de nanocristais de óxido de zincoinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisDantas, Noelio Oliveirahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4790290P3Tozoni, José Robertohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4736686Z3Franco Júnior, Adolfohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4781898Y0http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4235799U1Batista, Elisson Andrade81762556info:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFUinstname:Universidade Federal de Uberlândia (UFU)instacron:UFUTHUMBNAILSintesesCaracterizacoesNanocristais.pdf.jpgSintesesCaracterizacoesNanocristais.pdf.jpgGenerated Thumbnailimage/jpeg1227https://repositorio.ufu.br/bitstream/123456789/15673/3/SintesesCaracterizacoesNanocristais.pdf.jpg941c94339dd93ae950fcb5cec9557b42MD53ORIGINALSintesesCaracterizacoesNanocristais.pdfapplication/pdf6952953https://repositorio.ufu.br/bitstream/123456789/15673/1/SintesesCaracterizacoesNanocristais.pdf4752250d8586458e51515b10e1f38050MD51TEXTSintesesCaracterizacoesNanocristais.pdf.txtSintesesCaracterizacoesNanocristais.pdf.txtExtracted texttext/plain135148https://repositorio.ufu.br/bitstream/123456789/15673/2/SintesesCaracterizacoesNanocristais.pdf.txtf45e78fc126eb0b009a46ccc1669ab99MD52123456789/156732021-05-17 13:32:43.781oai:repositorio.ufu.br:123456789/15673Repositório InstitucionalONGhttp://repositorio.ufu.br/oai/requestdiinf@dirbi.ufu.bropendoar:2021-05-17T16:32:43Repositório Institucional da UFU - Universidade Federal de Uberlândia (UFU)false |
dc.title.por.fl_str_mv |
Sínteses e caracterizações de nanocristais de óxido de zinco |
title |
Sínteses e caracterizações de nanocristais de óxido de zinco |
spellingShingle |
Sínteses e caracterizações de nanocristais de óxido de zinco Batista, Elisson Andrade Nanocristais Óxido de zinco Precipitação química Solução aquosa Análise térmica diferencial Difração de raios-x Espectroscopia Raman Microscopia eletrônica de varredura Absorção óptica Fluorescência Análise térmica Nanocrystals Zinc oxide Chemical precipitation Aqueous solution Differential thermal analysis X-ray diffraction Raman spectroscopy Scanning electron microscopy Optical absorption Fluorescence CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA |
title_short |
Sínteses e caracterizações de nanocristais de óxido de zinco |
title_full |
Sínteses e caracterizações de nanocristais de óxido de zinco |
title_fullStr |
Sínteses e caracterizações de nanocristais de óxido de zinco |
title_full_unstemmed |
Sínteses e caracterizações de nanocristais de óxido de zinco |
title_sort |
Sínteses e caracterizações de nanocristais de óxido de zinco |
author |
Batista, Elisson Andrade |
author_facet |
Batista, Elisson Andrade |
author_role |
author |
dc.contributor.advisor1.fl_str_mv |
Dantas, Noelio Oliveira |
dc.contributor.advisor1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4790290P3 |
dc.contributor.referee1.fl_str_mv |
Tozoni, José Roberto |
dc.contributor.referee1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4736686Z3 |
dc.contributor.referee2.fl_str_mv |
Franco Júnior, Adolfo |
dc.contributor.referee2Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4781898Y0 |
dc.contributor.authorLattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4235799U1 |
dc.contributor.author.fl_str_mv |
Batista, Elisson Andrade |
contributor_str_mv |
Dantas, Noelio Oliveira Tozoni, José Roberto Franco Júnior, Adolfo |
dc.subject.por.fl_str_mv |
Nanocristais Óxido de zinco Precipitação química Solução aquosa Análise térmica diferencial Difração de raios-x Espectroscopia Raman Microscopia eletrônica de varredura Absorção óptica Fluorescência Análise térmica |
topic |
Nanocristais Óxido de zinco Precipitação química Solução aquosa Análise térmica diferencial Difração de raios-x Espectroscopia Raman Microscopia eletrônica de varredura Absorção óptica Fluorescência Análise térmica Nanocrystals Zinc oxide Chemical precipitation Aqueous solution Differential thermal analysis X-ray diffraction Raman spectroscopy Scanning electron microscopy Optical absorption Fluorescence CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA |
dc.subject.eng.fl_str_mv |
Nanocrystals Zinc oxide Chemical precipitation Aqueous solution Differential thermal analysis X-ray diffraction Raman spectroscopy Scanning electron microscopy Optical absorption Fluorescence |
dc.subject.cnpq.fl_str_mv |
CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA |
description |
In this work, Zinc oxide (ZnO) nanocrystals (NCs) were synthesized by chemical precipitation method by way of aqueous solution, adopting three synthesis temperatures (0°C, 25°C, and 100°C). After, the samples were annealed at 250°C, 500°C, and 750°C, for two hours. In order to study the effects of synthesis and annealing temperatures in the thermal, structural, morphological, and optical properties of these NCs were performed following characterizations: Differential thermal analysis (DTA), X-ray diffraction (XRD), Raman spectroscopy (Raman), scanning electron microscopy (SEM), optical absorption (OA), and fluorescence (FL). The DTA thermograms gave evidence that both the synthesis temperature as the annealing temperature influenced on the density of Zn(OH)2, crystallinity, density of defects, and morphology of ZnO NCs. The XRD patterns gave strong indications of the majority formation of ZnO NCs with wurtzite structure (JCPDS 36-1451). Next, the Zn(OH)2, in the samples, according to the DTA thermograms, probably was in the amorphous phase. It was found that both the synthesis temperature as the annealing temperature did not change the crystalline structure of the ZnO NCs, however, influenced the crystallinity and the size. The Raman spectra reinforced the results obtained by XRD, with respect to the crystal structure of ZnO NCs, and it was observed that both the synthesis temperature as the heat treatment influenced the degree of disorder and density of oxygen vacancies. It was observed in the SEM pictures that both the synthesis temperature as the annealing temperature changed the morphology and influenced both the size dispersion as the size of the NCs ZnO. The behavior of NCs size is acording with the XRD results. The AO spectra gave indications that the ZnO NCs presented quantum confinement properties, being in agreement with the results of XRD and SEM. The FL spectra reinforced the indications, given from the AO spectra, that the NCs showed quantum confinement properties and that both the synthesis temperature as the annealing temperature influenced the densities of Zn(OH)2, according to the DTA thermograms, and oxygen vacancies, according to the Raman spectra. Moreover, it was possible to establish the relationship between the synthesis and annealing temperatures with the density of energy levels due to various defects in the structure of the NCS. Thus, according to these results, it was possible to control the thermal, structural, morphological, and optical properties of ZnO NCs, synthesized by chemical precipitation method in aqueous solution, from the varying the synthesis and annealing temperatures. It is believed that these results can arouse great interest in scientific research, as the synthesis and processing of ZnO NCs from the methodology adopted in this work, enabling their use in various technological applications. |
publishDate |
2015 |
dc.date.available.fl_str_mv |
2015-03-19 2016-06-22T18:43:13Z |
dc.date.issued.fl_str_mv |
2015-02-23 |
dc.date.accessioned.fl_str_mv |
2016-06-22T18:43:13Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
BATISTA, Elisson Andrade. Sínteses e caracterizações de nanocristais de óxido de zinco. 2015. 84 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de Uberlândia, Uberlândia, 2015. Disponível em: https://doi.org/10.14393/ufu.di.2015.89 |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufu.br/handle/123456789/15673 |
dc.identifier.doi.por.fl_str_mv |
https://doi.org/10.14393/ufu.di.2015.89 |
identifier_str_mv |
BATISTA, Elisson Andrade. Sínteses e caracterizações de nanocristais de óxido de zinco. 2015. 84 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de Uberlândia, Uberlândia, 2015. Disponível em: https://doi.org/10.14393/ufu.di.2015.89 |
url |
https://repositorio.ufu.br/handle/123456789/15673 https://doi.org/10.14393/ufu.di.2015.89 |
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por |
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openAccess |
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Universidade Federal de Uberlândia |
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Programa de Pós-graduação em Física |
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UFU |
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BR |
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Ciências Exatas e da Terra |
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Universidade Federal de Uberlândia |
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