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Previous issue date: 2016-05-05 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Nas ?ltimas d?cadas tem se observado um enorme interesse no estudo de materiais cer?micos nanoestruturados com propriedades fotocatal?ticas e fotoluminescentes. Um dos precursores ? o di?xido de tit?nio (TiO2) que possui propriedades ?pticas, por?m apresenta alto valor de band gap (3.2 eV), combinando-o com outros ?xidos como o ?xido de ?ndio (In2O3) intensificar? suas propriedades, j? que o In2O3 possui menor band gap (2,8 eV), al?m de apresentar absor??o no vis?vel sendo eficaz para aumentar a absor??o do TiO2. Neste trabalho o m?todo de spin-coating foi utilizado na deposi??o de filmes finos multicamadas de TiO2/In2O3. Na prepara??o dos filmes, foram utilizadas resinas obtidas pelo m?todo de polimeriza??o de complexos (MCP), as quais tiveram sua viscosidade ajustada em 20cps. As resinas foram depositadas sobre o substrato de sil?cio (Si) variando em 4, 8 e 16 camadas, logo ap?s, foram cristalizadas em diferentes temperaturas 300?C, 500?C e 700?C. A caracteriza??o dos filmes foi feita por meio de difra??o de Raios-X (DRX), microscopia eletr?nica de varredura com emiss?o de campo (MEV-FEG), microscopia de for?a at?mica (AFM), espectroscopia na regi?o do UV-V?sivel (UV-Vis) e medidas de fotoluminesc?ncia (FL). Os resultados de difra??o de Raios-X confirmaram a forma??o do TiO2 com fase anatase e do In2O3, n?o havendo intera??o qu?mica entre os ?xidos dos filmes. As imagens obtidas por microscopia de for?a at?mica mostraram filmes bem densificados com tamanho m?dio de gr?o variando de 15 a 35 nm. As imagens da se??o transversal dos filmes de TiO2/In2O3 cristalizados a 700?C indicam espessuras bem uniformes variando de 262 a 708nm entre amostras. A atividade fotocatal?tica dos filmes foi avaliada atrav?s da degada??o do corante azul de metileno, os resultados indicaram que os filmes conferiram boa atividade fotocatal?tica na decomposi??o do azul de metileno. Os espectros de fotoluminesc?ncia apresentaram emiss?es correspondentes na regi?o do azul, resultado confirmado atrav?s do diagrama de cromaticidade. / In recent decades it has seen a huge interest in the study of nanostructured ceramic materials with photocatalytic and photoluminescent properties. A precursor is titanium dioxide (TiO2) having optical properties but has a high value of band gap (3.2 eV), combining them with other oxides such as indium oxide (In2O3) intensify their properties, as the In2O3 it has a smaller band gap (2.8 eV), and presents the visible absorption being effective to increase the absorption of the TiO2. In this work the spin-coating method was used in the deposition of multilayer thin films of TiO2 / In2O3. In the preparation of films, resins used were obtained by the complex polymerization method (CPM) which had a viscosity of 20cps adjusted. The resins were deposited on the silicon substrate (Si) ranging in 4, 8 and 16 layers there upon were crystallized at different temperatures 300?C, 500?C and 700?C. The characterization of the films was made by diffraction of X-rays (XRD), scanning electron microscopy, field emission (SEM-FEG), atomic force microscopy (AFM), spectroscopy in the UV-Visible region (UV- Vis) and photoluminescence measurements (PL). The results of X-ray diffraction confirmed the formation of anatase TiO2 with and In2O3 phase, there is no chemical interaction between the oxides of the films. The images obtained by atomic force microscopy showed well densified film with average grain size ranging from 15 to 35 nm. The images of the cross section of the film TiO2/In2O3 crystallized at 700?C indicated a uniform thickness ranging from 262 to 708nm between samples. The photocatalytic activity of the films was evaluated by the degradation of methylene blue dye, the results indicated that the film gave good photocatalytic activity in the decomposition of methylene blue, and increasing the number of layers had no significant influence on the increase in activity photocatalytic. The films were recycled and reused for three cycles photobleaching. The results were quite significant, as demonstrated the feasibility of reuse of thin films in the dye photobleaching. The photoluminescent properties of the films was studied at room temperature using excitation wavelength of 350 nm. The thin films studied had broadband issue. A high photoluminescent intensity was observed for the films annealed at 700 ? C in the different variations of the layer numbers. From the results obtained it was observed the feasibility of using the thin film as a photocatalytic material.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/21415 |
| Date | 05 May 2016 |
| Creators | Garcia, Laurenia Martins Pereira |
| Contributors | 24779953839, http://lattes.cnpq.br/9918299069511517, Paskocimas, Carlos Alberto, 06296687877, http://lattes.cnpq.br/2365059843175411, Ruiz, Juan Alberto Chavez, 00744293456, http://lattes.cnpq.br/7463463383362150, Ara?jo, Vin?cius Dantas de, 32864249863, http://lattes.cnpq.br/9752753965948564, Delmonte, Maur?cio Roberto Bomio, Motta, Fabiana Villela da |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE MATERIAIS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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