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Master's Dissertation
DOI
https://doi.org/10.11606/D.85.2020.tde-05112020-170759
Document
Author
Full name
Paula Maria da Silva
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2020
Supervisor
Committee
Júnior, Rubens Nunes de Faria (President)
Casini, Julio César Serafim
Marcondes, Paulo Victor Prestes
Title in Portuguese
Obtenção de eletrodos nanoestruturados de ZnO para aplicação em células fotovoltaicas
Keywords in Portuguese
CBD
célula solar sensibilizada por corante
nanoestruturas
SILAR
ZnO
Abstract in Portuguese
A necessidade por energia elétrica tem impulsionado a pesquisa por fontes renováveis e sustentáveis para a geração de energia, como a energia solar. Neste sentido, as células solares sensibilizadas por corante (DSSC, do inglês Dye Sensitized Solar Cell) são promissoras por fornecer energia sobre qualquer intensidade luminosa. O óxido de zinco (ZnO) é um semicondutor do tipo n estudado para emprego nesses dispositivos por ser um material atóxico, barato e ambientalmente amigável, além de ter banda proibida de 3,7 eV. Este trabalho objetivou a obtenção de eletrodos de ZnO nanoestruturados seguindo os seguintes métodos: SILAR, do inglês, successive ionic layer adsorption and reaction, para obtenção da semente e; CBD, do inglês, chemical bath deposition, para crescimento da nanoestrutura. Para a síntese das nanoestruturas foi utilizado como precursores: acetato de zinco dihidratado, cloreto de zinco, sulfato de zinco heptahidratado e nitrato de zinco hexahidratado. Para cada precursor utilizado foram obtidos fotoanodos de filmes nanoestruturados com morfologias distintas com espessura da ordem de 10 µm, com orientação preferencial na direção do eixo basal <0002> e fotoanodos com o material particulado filtrado do banho químico. Estes fotoanodos foram caracterizados por microscopia eletrônica de varredura, microscopia de força atômica, fluorescência de raios X e difração de raio X. As DSSCs confeccionadas com fotoanodos de ZnO nanoestruturados mostraram que os mecanismos de transporte de cargas foram influenciados pela morfologia do ZnO. O material particulado originário dos sais de cloreto e nitrato de zinco apresentaram morfologia semelhante após a cominuição resultando em DSSCs semelhantes. A DSSC do pó de sulfato de zinco apresentou os melhores parâmetros elétricos e a maior eficiência (η = 0,71 ± 0,02 %).
Title in English
Synthesis of ZnO nanostructured electrodes for use in photovoltaic cells
Keywords in English
dye sensitized solar cells
nanostructures
ZnO
Abstract in English
The increasing energy demand has motivated the research for renewable and sustainable sources for energy generation, such as solar energy. In this aspect, the dye sensitized solar cells (DSSC) are promising due its ability of providing energy over any light intensity. Zinc oxide (ZnO) is a well-studied n type semiconductor for use in these devices because it is a nontoxic material, inexpensive and environmental friendly, besides its physical characteristics, such as: band gap of 3,7 eV. The aim of this work was to synthesize ZnO nanostructured electrodes using the methods: Successive Ionic Layer Adsorption and Reaction (SILAR), for the seeds synthesis; and Chemical Bath Deposition (CBD), for the nanostructures growth. The nanostructures were synthesized using the precursors: zinc acetate dihydrate, zinc chloride, zinc sulfate heptahydrate and zinc nitrate hexahydrate. For each precursor, the photoanodes with distinct morphologies according to the zinc salt studied, 10 µm thick and with preferential orientation along the basal axis <0002> were obtained, and also photoanodes were obtained using the particulate material filtered from the chemical bath. The photoanodes were characterized by scanning electron microscopy, atomic force microscopy, X-ray fluorescence, and X-ray diffraction. The DSSC prepared using ZnO nanostructured photoanodes showed that the charge transport mechanism was influenced by the ZnO morphology. The particulate material from the chloride and nitrate zinc salts showed similar morphology after comminution, which resulted similar DSSCs. The DSSC produced using the de zinc sulfate powder presented the best electric parameters and it was the most efficient (η = 0,71 ± 0,02 %).
 
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2020SilvaObtencao.pdf (4.97 Mbytes)
Publishing Date
2020-11-27
 
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