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Previous issue date: 2014-08-29 / The main goal of the solar cell industry is to reduce the production costs so that the photovoltaic solar energy can be competitive with other kinds of electricity generation. Currently, many industrial silicon solar cells use p-type wafers and have a thickness of approximately 200 μm. The combination of the use of n-type silicon to obtain higher efficiency devices and thinner wafers can be an alternative for reducing costs. The aim of this work was to develop and evaluate silicon solar cells fabricated in thin wafers of n-type Czochralski-growth monocrystalline solar grade silicon, specifically in the development of the manufacturing process of p+nn+ and n+np+ solar cells. An etching based on 100 g of KOH and 1600 mL of H2O kept at 85 ?C was experimentally suited for thinning 200 μm wafers. Seven minutes in the etching were needed for obtaining 135 μm 140 μm thick wafers. The time of the standard texture etch used in the NT-Solar was optimized and the time that produced the lower reflectance was 40 min. By comparing metal pastes of Ag, Ag/Al and Al, we concluded that the latter enabled the manufacture of the more efficient solar cells, with both structures and aluminum metal paste cannot etch-through the TiO2 thin film. This way, the Al paste has to be deposited on the p+ face before the deposition of this film. The firing of the Ag and Al metal pastes were optimized taking into account the firing temperature. The higher average efficiencies were observed when the firing temperature remained in the range of 870 ?C a 890 ?C. More efficient solar cells fabricated with n+np+ and p+nn+ structures achieved the efficiency of 13.8 % and 13.2 %, respectively. The internal quantum efficiency showed the solar cells presented high surface recombination. By comparing both structures obtained with similar processes, we can conclude that n+np+ is the most suitable to the production of ntype silicon solar cells. / O principal objetivo da ind?stria de c?lulas solares ? reduzir os custos de produ??o a fim de que a energia solar fotovoltaica possa ser competitiva com outras formas de produ??o de energia el?trica. Atualmente, a maioria das c?lulas solares industriais de sil?cio utilizam l?minas tipo p e estas possuem espessura da ordem 200μm. A combina??o do uso de sil?cio tipo n para a obten??o de dispositivos de maior efici?ncia e l?minas finas podem ser alternativas para a redu??o dos custos. Este trabalho teve por objetivo desenvolver e avaliar c?lulas solares fabricadas sobre l?minas finas de sil?cio monocristalino Czochralski, grau solar, tipo n, especificamente no desenvolvimento do processo para fabrica??o de c?lulas p+nn+ e n+np+. Adaptou-se experimentalmente um ataque qu?mico baseado em 100 g de KOH dilu?dos em 1600 mL de H2O para afinamento de l?minas de 200 μm, sendo necess?rios 7 min de imers?o com a solu??o a 85 ?C para obten??o de l?minas de 135 μm 140 μm. A textura??o padr?o do NT-Solar foi usada, sendo que o tempo de processo que produziu a menor reflet?ncia foi de 40 min. Ao comparar pastas de Ag, Ag/Al e Al, constatou-se que a ?ltima permitiu a fabrica??o das c?lulas solares mais eficientes, com ambas as estruturas. Observou-se que esta pasta n?o consegue perfurar o filme de TiO2 e a mesma deve ser depositada sobre a face p+ antes da deposi??o deste filme. A queima de pastas met?licas de Ag e Al foi otimizada considerando a temperatura do processo t?rmico e concluiu-se que esta deve estar no intervalo de 870 ?C a 890 ?C, onde se observou a efici?ncia m?dia mais alta. As c?lulas solares mais eficientes fabricadas com as estruturas n+np+ e p+nn+ atingiram a efici?ncia de 13,8 % e 13,2 %, respectivamente. A efici?ncia qu?ntica interna mostrou que as c?lulas solares t?m alta recombina??o nas superf?cies. Comparando ambas as estruturas obtidas por processos similares, conclui-se que a estrutura n+np+ ? a mais adequada para produ??o de c?lulas solares finas em base n.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/3265 |
| Date | 29 August 2014 |
| Creators | Campos, Rodrigo Carvalho de |
| Contributors | Moehlecke, Adriano |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Engenharia e Tecnologia de Materiais, PUCRS, BR, Faculdade de Engenharia |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -7432719344215120122, 500, 600, -655770572761439785 |
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