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Title:
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ECN N-type silicon solar cell technology: an industrial process that yields 18.5%
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Author(s):
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Published by:
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Publication date:
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ECN
Solar Energy
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9-6-2009
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ECN report number:
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Document type:
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ECN-M--09-073
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Conference Paper
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Number of pages:
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Full text:
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3
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Download PDF
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Presented at: 34th IEEE Photovoltaic Specialists Conference, Philadelphia, USA, 7-12 juni 2009.
Abstract:
There is currently much interest in n-type solar cells because of the advantages of this material. N-type material is expected to be more favourable for obtaining high efficiencies than p-type doped substrates. We have developed a process for n-type solar cells for large area multicrystalline and monocrystalline silicon wafers. The production process is based on industrial processing steps such as screen-printed metallization and firing through. The surfaces of these cells are passivated with a layer stack consisting of SiO2 and SiNx where the former is created by a wet chemical process and the latter by inline PECVD. We demonstrate that the surface passivation can be improved with an alternative wet chemical process for creating the SiO2 layer. This new process results in an enhancement of the implied Voc of unmetallized cells as measured by quasi-steady-state photoconductance (QSSPC) and the Voc of completed cells. The process Improvements have yielded a new record efficiency of 18.5 % (for a particular rear reflection surface) that was independently confirmed by Fraunhofer ISE CalLab.
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