Preparação e caracterização estrutural e elétrica de células solares sensibilizadas por corantes empregando anodos nanoestruturados à base de 'TiO IND. 2'
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Data
2011-06-03
Autores
Muniz, Elaine Cristina [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Células solares sensibilizadas por corante são dispositivos capazes de converter energia solar em energia elétrica e/ou química e por isso despontam como uma alternativa promissora para geração de energia. As características do filme semicondutor utilizado como anodo nessas células, dentre as quais podemos citar a espessura, a área superficial e a porosidade, interferem significativamente em seu desempenho. Dessa forma, o controle e a reprodutibilidade na preparação dos filmes semicondutores foram o primeiro objetivo dessa etapa deste projeto de mestrado. Para isso foram preparadas dispersões coloidais de dióxido de titânio, utilizando o método sol-gel combinado com o método hidrotermal. A dispersão de TiO2 resultante foi depositada por screen-printing sobre substratos condutores (substratos de vidro recobertos com um filme fino de óxido de estanho dopado com flúor). A metodologia utilizada permitiu a obtenção de filmes mesoporosos, com elevada área superficial e com espessura de 10,3 (±0,5) μm. O controle das características do filme semicondutor permitiu a construção (com reprodutibilidade) de células com eficiência de conversão média igual a 5,1 (±0,2) %. Em outra etapa do trabalho, o objetivo foi minimizar os processos de recombinação eletrônica que ocorrem nas interfaces (i) semicondutor/eletrólito e (ii) substrato condutor/eletrólito. Para isso, as partículas do semicondutor foram recobertos com Al2O3 (estrutura tipo núcleo-camada) e os substratos condutores com finas camadas de TiO2 (camadas de barreira). No primeiro caso, as partículas de TiO2 obtidas na primeira etapa do trabalho foram recobertas com Al2O3 por dip-coating utilizando dispersões com diferentes concentrações de Al2O3 (0,15 mol L-1 e 0,0075 mol L-1). Um aumento de aproximadamente 11% na eficiência...
Dye-sensitized solar cells are devices capable of converting solar energy into electrical and/or chemical energy and so forth with a promising alternative for power generation. The characteristics of the semiconductor film used as anode in these cells, among which we mention the thickness, surface area and porosity, significantly interfere with their performance. Thus, the control and reproducibility in the preparation of semiconductor films were the main goals of this part of the project. Therefore colloidal dispersions of titanium dioxide were prepared by the sol-gel method combined with the hydrothermal method. The resulting dispersion of TiO2 was deposited by screen-printing on conductive substrates (glass substrates coated with a thin film of tin oxide doped with fluorine). This methodology allowed the preparation of mesoporous films with high surface area and thickness of 10.3 (± 0.5) micrometers. The control of the characteristics of the semiconductor film allowed the construction (reproductively) of cells with an average conversion efficiency of 5.1 (± 0.2)%. At the second part of the work, the goal was to minimize electron recombination processes that occur at the following interfaces (i) semiconductor/electrolyte and (ii) conducting substrate/electrolyte. Therefore, the TiO2 semiconductor particles were coated with Al2O3 (using the core-shell strategy) and the conductive substrates with thin layers of TiO2 (acting as barrier). In this case the TiO2 particles obtained in the first stage of this study were coated with Al2O3 by dip-coating using dispersions with different concentrations of Al2O3 (0.15 mol L-1 and 0.0075 mol L-1). An increase of approximately 11% conversion efficiency was observed in DSCs assembled using the anodes with lower concentration of Al2O3. This fact... (Complete abstract click electronic access below)
Dye-sensitized solar cells are devices capable of converting solar energy into electrical and/or chemical energy and so forth with a promising alternative for power generation. The characteristics of the semiconductor film used as anode in these cells, among which we mention the thickness, surface area and porosity, significantly interfere with their performance. Thus, the control and reproducibility in the preparation of semiconductor films were the main goals of this part of the project. Therefore colloidal dispersions of titanium dioxide were prepared by the sol-gel method combined with the hydrothermal method. The resulting dispersion of TiO2 was deposited by screen-printing on conductive substrates (glass substrates coated with a thin film of tin oxide doped with fluorine). This methodology allowed the preparation of mesoporous films with high surface area and thickness of 10.3 (± 0.5) micrometers. The control of the characteristics of the semiconductor film allowed the construction (reproductively) of cells with an average conversion efficiency of 5.1 (± 0.2)%. At the second part of the work, the goal was to minimize electron recombination processes that occur at the following interfaces (i) semiconductor/electrolyte and (ii) conducting substrate/electrolyte. Therefore, the TiO2 semiconductor particles were coated with Al2O3 (using the core-shell strategy) and the conductive substrates with thin layers of TiO2 (acting as barrier). In this case the TiO2 particles obtained in the first stage of this study were coated with Al2O3 by dip-coating using dispersions with different concentrations of Al2O3 (0.15 mol L-1 and 0.0075 mol L-1). An increase of approximately 11% conversion efficiency was observed in DSCs assembled using the anodes with lower concentration of Al2O3. This fact... (Complete abstract click electronic access below)
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Físico-química, Physical chemistry
Como citar
MUNIZ, Elaine Cristina. Preparação e caracterização estrutural e elétrica de células solares sensibilizadas por corantes empregando anodos nanoestruturados à base de 'TiO IND. 2'. 2011. 89 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Química, 2011.