Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3
Ano de defesa: | 2023 |
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Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | |
Tipo de documento: | Tese |
Tipo de acesso: | Acesso aberto |
Idioma: | por |
Instituição de defesa: |
Não Informado pela instituição
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Programa de Pós-Graduação: |
Pós-Graduação em Física
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Departamento: |
Não Informado pela instituição
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País: |
Não Informado pela instituição
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Palavras-chave em Português: | |
Palavras-chave em Inglês: | |
Área do conhecimento CNPq: | |
Link de acesso: | http://ri.ufs.br/jspui/handle/riufs/17469 |
Resumo: | Cadmium Metasilicate (CdSiO3) is a material with luminescent properties that has great potential for applications in several areas, such as emergency lights, decoration, luminescent pigments, ceramic coatings for use in radiodiagnosis rooms, scintillators, optoelectronics devices, thermometers for cryogenic temperatures, among others. The main aim of this work was to investigate the best synthesis condition using the sol-gel synthesis with pH variation of the precursor solution, as well as to study the resulting optical properties in order to understand the influence of the hydrolysis and polycondensation mechanisms in the active luminescent channels present in this material, responsible for its intrinsic luminescence. The single crystalline phase of CdSiO3 was obtained for samples calcined at 1000 °C for 3 h in an open atmosphere, when produced at pH 1 and 3, and mostly, for cases of pH 5, 7, and 9, with about 3% of SiO2 as a secondary phase. These data were obtained through XRD measurements and Rietveld Refinement analysis. The morphology was investigated by means of SEM and TEM being observed depending on the pH. The optical properties were investigated through measurements of optical absorption (AO), in order to understand how the samples behaved when they were irradiated with different doses. Photoluminescence (PL) in the temperature range between 62 K and 300 K, was performed at LNLS. PL measurements were performed on excitation ranges from 4.5 to 7.0 eV (275 to 165 nm) and emission energies from 1.7 to 4.1 eV (730 to 302 nm). The behavior of PL emission as a function of temperature and excitation energies clearly indicated that the intrinsic luminescence of CdSiO3 is composed of four emission channels with maxima centered around 2.10 eV (peak 1), 2.66 eV (peak 2), 3.07 eV (peak 3), and 3.48 eV (peak 4). Peaks 1 and 2 are due to charges trapped in the Cd and O vacancies, and peaks 3 and 4 are due to self-trapped excitons (STE) generated after excitation and trapped in the Cd and O vacancies. The PL results as a function of temperature indicated that CdSiO3 can be explored as a contactless thermometer for cryogenic applications. Radioluminescence (RL) was used in order to understand the behavior of the luminescent channels when they are being excited by X-rays, and the emission, right after the excitation ceased. |
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Melo, Simone SantosValerio, Mário Ernesto Giroldo2023-04-25T19:34:28Z2023-04-25T19:34:28Z2023-02-28MELO, Simone Santos. Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3. 2023. 163 f. Tese (Doutorado em Física) – Universidade Federal de Sergipe, São Cristóvão, 2023.http://ri.ufs.br/jspui/handle/riufs/17469Cadmium Metasilicate (CdSiO3) is a material with luminescent properties that has great potential for applications in several areas, such as emergency lights, decoration, luminescent pigments, ceramic coatings for use in radiodiagnosis rooms, scintillators, optoelectronics devices, thermometers for cryogenic temperatures, among others. The main aim of this work was to investigate the best synthesis condition using the sol-gel synthesis with pH variation of the precursor solution, as well as to study the resulting optical properties in order to understand the influence of the hydrolysis and polycondensation mechanisms in the active luminescent channels present in this material, responsible for its intrinsic luminescence. The single crystalline phase of CdSiO3 was obtained for samples calcined at 1000 °C for 3 h in an open atmosphere, when produced at pH 1 and 3, and mostly, for cases of pH 5, 7, and 9, with about 3% of SiO2 as a secondary phase. These data were obtained through XRD measurements and Rietveld Refinement analysis. The morphology was investigated by means of SEM and TEM being observed depending on the pH. The optical properties were investigated through measurements of optical absorption (AO), in order to understand how the samples behaved when they were irradiated with different doses. Photoluminescence (PL) in the temperature range between 62 K and 300 K, was performed at LNLS. PL measurements were performed on excitation ranges from 4.5 to 7.0 eV (275 to 165 nm) and emission energies from 1.7 to 4.1 eV (730 to 302 nm). The behavior of PL emission as a function of temperature and excitation energies clearly indicated that the intrinsic luminescence of CdSiO3 is composed of four emission channels with maxima centered around 2.10 eV (peak 1), 2.66 eV (peak 2), 3.07 eV (peak 3), and 3.48 eV (peak 4). Peaks 1 and 2 are due to charges trapped in the Cd and O vacancies, and peaks 3 and 4 are due to self-trapped excitons (STE) generated after excitation and trapped in the Cd and O vacancies. The PL results as a function of temperature indicated that CdSiO3 can be explored as a contactless thermometer for cryogenic applications. Radioluminescence (RL) was used in order to understand the behavior of the luminescent channels when they are being excited by X-rays, and the emission, right after the excitation ceased.O metassilicato de cádmio (CdSiO3) é um material com propriedades luminescentes que apresenta grande potencial para aplicações em diversas áreas, como, por exemplo, sinalização de emergência, decoração, pigmentos luminescentes, revestimentos cerâmicos, para uso em salas de radiodiagnósticos, cintiladores, armazenamento óptico de dados, termômetros para temperaturas criogênicas, entre outras. Este trabalho teve como objetivo principal investigar a melhor condição de síntese usando a síntese sol-gel com variação do pH da solução precursora, bem como estudar as propriedades ópticas resultantes, a fim de compreender a influência dos mecanismos de hidrólise e policondensação presentes nos canais luminescentes ativos neste material, responsáveis por sua luminescência intrínseca. A fase cristalina pura do CdSiO3 foi obtida para amostras calcinadas a 1000 °C por 3 h em atmosfera aberta, quando produzidas no pH 1 e 3, e majoritariamente, para o pH 5, 7 e 9, com cerca de 3% de SiO2 como fase secundária. Estes dados foram obtidos por meio de medidas de DRX e análises de Refinamento Rietveld. A morfologia foi investigada por meio de MEV e MET sendo observadas dependência com o pH. As propriedades ópticas foram investigadas por meio de medidas de absorção óptica (AO), a fim de compreender como as amostras se comportavam quando eram irradiadas com diferentes doses. Fotoluminescência (PL), no intervalo de temperatura entre 62 K e 300 K, foram realizadas no LNLS. As medidas de PL foram realizadas para faixas de excitação de 4,5 a 7,0 eV (275 a 165 nm) e energias de emissão de 1,7 a 4,1 eV (730 a 302 nm). O comportamento da emissão do PL em função da temperatura e das energias de excitação indicou claramente que a luminescência intrínseca do CdSiO3 é composta por quatro canais de emissão com máximos centrados em torno de 2,10 eV (pico 1), 2,66 eV (pico 2), 3,07 eV (pico 3) e 3,48 eV (pico 4). Os picos 1 e 2 são devidos a cargas aprisionadas nas vacâncias de Cd e O e os picos 3 e 4 são devidos a éxcitons auto aprisionado (STE) gerados após a excitação e armadilhados nas vacâncias de Cd e O. Os resultados de PL em função da temperatura indicaram que o CdSiO3 pode ser explorado como um termômetro de fluorescência sem contato para aplicações criogênicas. Radioluminescência (RL) foi utilizada com o intuito de compreender o comportamento dos canais luminescentes quando esses estão sendo excitados por raios X, e da emissão logo após cessada a excitação.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESComissão Nacional de Energia Nuclear - CNENSão CristóvãoporMetassilicato de cádmioSíntese sol-gelVariação do pHDefeitos intrínsecosFotoluminescênciaCintiladoresCadmium metasilicateSol-gel synthesisPH variationIntrinsic defectsPhotoluminescenceScintillatorsCIENCIAS EXATAS E DA TERRA::FISICAInfluência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisPós-Graduação em FísicaUniversidade Federal de Sergipereponame:Repositório Institucional da UFSinstname:Universidade Federal de Sergipe (UFS)instacron:UFSinfo:eu-repo/semantics/openAccessLICENSElicense.txtlicense.txttext/plain; charset=utf-81475https://ri.ufs.br/jspui/bitstream/riufs/17469/1/license.txt098cbbf65c2c15e1fb2e49c5d306a44cMD51ORIGINALSIMONE_SANTOS_MELO.pdfSIMONE_SANTOS_MELO.pdfapplication/pdf20631056https://ri.ufs.br/jspui/bitstream/riufs/17469/2/SIMONE_SANTOS_MELO.pdf1f91bfe5dedcf48f0945c5d71bc99a07MD52TEXTSIMONE_SANTOS_MELO.pdf.txtSIMONE_SANTOS_MELO.pdf.txtExtracted texttext/plain276644https://ri.ufs.br/jspui/bitstream/riufs/17469/3/SIMONE_SANTOS_MELO.pdf.txtcbb67b6405987e7e8cde3c45309dda41MD53THUMBNAILSIMONE_SANTOS_MELO.pdf.jpgSIMONE_SANTOS_MELO.pdf.jpgGenerated Thumbnailimage/jpeg1350https://ri.ufs.br/jspui/bitstream/riufs/17469/4/SIMONE_SANTOS_MELO.pdf.jpga73d80745e2f4adaf1a7db3d479403a0MD54riufs/174692023-04-25 16:38:54.784oai:ufs.br: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Repositório InstitucionalPUBhttps://ri.ufs.br/oai/requestrepositorio@academico.ufs.bropendoar:2023-04-25T19:38:54Repositório Institucional da UFS - Universidade Federal de Sergipe (UFS)false |
dc.title.pt_BR.fl_str_mv |
Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3 |
title |
Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3 |
spellingShingle |
Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3 Melo, Simone Santos Metassilicato de cádmio Síntese sol-gel Variação do pH Defeitos intrínsecos Fotoluminescência Cintiladores Cadmium metasilicate Sol-gel synthesis PH variation Intrinsic defects Photoluminescence Scintillators CIENCIAS EXATAS E DA TERRA::FISICA |
title_short |
Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3 |
title_full |
Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3 |
title_fullStr |
Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3 |
title_full_unstemmed |
Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3 |
title_sort |
Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3 |
author |
Melo, Simone Santos |
author_facet |
Melo, Simone Santos |
author_role |
author |
dc.contributor.author.fl_str_mv |
Melo, Simone Santos |
dc.contributor.advisor1.fl_str_mv |
Valerio, Mário Ernesto Giroldo |
contributor_str_mv |
Valerio, Mário Ernesto Giroldo |
dc.subject.por.fl_str_mv |
Metassilicato de cádmio Síntese sol-gel Variação do pH Defeitos intrínsecos Fotoluminescência Cintiladores |
topic |
Metassilicato de cádmio Síntese sol-gel Variação do pH Defeitos intrínsecos Fotoluminescência Cintiladores Cadmium metasilicate Sol-gel synthesis PH variation Intrinsic defects Photoluminescence Scintillators CIENCIAS EXATAS E DA TERRA::FISICA |
dc.subject.eng.fl_str_mv |
Cadmium metasilicate Sol-gel synthesis PH variation Intrinsic defects Photoluminescence Scintillators |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::FISICA |
description |
Cadmium Metasilicate (CdSiO3) is a material with luminescent properties that has great potential for applications in several areas, such as emergency lights, decoration, luminescent pigments, ceramic coatings for use in radiodiagnosis rooms, scintillators, optoelectronics devices, thermometers for cryogenic temperatures, among others. The main aim of this work was to investigate the best synthesis condition using the sol-gel synthesis with pH variation of the precursor solution, as well as to study the resulting optical properties in order to understand the influence of the hydrolysis and polycondensation mechanisms in the active luminescent channels present in this material, responsible for its intrinsic luminescence. The single crystalline phase of CdSiO3 was obtained for samples calcined at 1000 °C for 3 h in an open atmosphere, when produced at pH 1 and 3, and mostly, for cases of pH 5, 7, and 9, with about 3% of SiO2 as a secondary phase. These data were obtained through XRD measurements and Rietveld Refinement analysis. The morphology was investigated by means of SEM and TEM being observed depending on the pH. The optical properties were investigated through measurements of optical absorption (AO), in order to understand how the samples behaved when they were irradiated with different doses. Photoluminescence (PL) in the temperature range between 62 K and 300 K, was performed at LNLS. PL measurements were performed on excitation ranges from 4.5 to 7.0 eV (275 to 165 nm) and emission energies from 1.7 to 4.1 eV (730 to 302 nm). The behavior of PL emission as a function of temperature and excitation energies clearly indicated that the intrinsic luminescence of CdSiO3 is composed of four emission channels with maxima centered around 2.10 eV (peak 1), 2.66 eV (peak 2), 3.07 eV (peak 3), and 3.48 eV (peak 4). Peaks 1 and 2 are due to charges trapped in the Cd and O vacancies, and peaks 3 and 4 are due to self-trapped excitons (STE) generated after excitation and trapped in the Cd and O vacancies. The PL results as a function of temperature indicated that CdSiO3 can be explored as a contactless thermometer for cryogenic applications. Radioluminescence (RL) was used in order to understand the behavior of the luminescent channels when they are being excited by X-rays, and the emission, right after the excitation ceased. |
publishDate |
2023 |
dc.date.accessioned.fl_str_mv |
2023-04-25T19:34:28Z |
dc.date.available.fl_str_mv |
2023-04-25T19:34:28Z |
dc.date.issued.fl_str_mv |
2023-02-28 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
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doctoralThesis |
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publishedVersion |
dc.identifier.citation.fl_str_mv |
MELO, Simone Santos. Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3. 2023. 163 f. Tese (Doutorado em Física) – Universidade Federal de Sergipe, São Cristóvão, 2023. |
dc.identifier.uri.fl_str_mv |
http://ri.ufs.br/jspui/handle/riufs/17469 |
identifier_str_mv |
MELO, Simone Santos. Influência do pH na formação dos defeitos pontuais responsáveis pela luminescência intrínseca do CdSiO3. 2023. 163 f. Tese (Doutorado em Física) – Universidade Federal de Sergipe, São Cristóvão, 2023. |
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http://ri.ufs.br/jspui/handle/riufs/17469 |
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Pós-Graduação em Física |
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Universidade Federal de Sergipe |
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