ECN publication
Title:
Roll to roll nanotexturization of layers on steel foil substrates for NIP silicon solar cells
 
Author(s):
Heijna, M.; Goris, M.J.A.A.; Soppe, W.J.; Schipper, W.; Wilde, R.
 
Published by: Publication date:
ECN Solar Energy 6-9-2010
 
ECN report number: Document type:
ECN-M--10-024 Conference Paper
 
Number of pages: Full text:
4 Download PDF  

Presented at: 25th European Photovoltaic Solar Energy Conference and Exhibition - 5th World Conference on Photovoltaic Energy Conversion, Valencia, Spain, 6-10 september 2010.

Abstract:
Light management is of utmost importance for thin film silicon solar cells. For nip cells, light management can be provided by textured back reflectors. In this paper, we demonstrate the fabrication of textured back contact foil on an industry compatible scale. A UV-curing lacquer on a stretch of 80 m of 30 cm wide steel foil was nanotextured in roll-to-roll mode, using the contact imprint method. Lab-scale samples were textured statically to test the effect on the growth of silicon by PECVD and cell efficiencies. The light trapping effect increases with decreasing lateral feature size. High aspect ratio structures result in strong domain boundaries defined by the period of the gratings and in non-conformal growth of the active layers of the cell. In its turn, this non-conformal growth, with thinner coverage of the steep slopes of the texture can lead to shunting problems in the solar cells. So, a balance needs to be found between optimum light scattering of the textured back contact and optimum layer growth on that back contact.


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