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21.4% Efficient Fully Screen Printed n-Type Solar Cell on Epitaxially Grown Silicon Wafers With Built-In Boron Rear Side Emitter
V. Mertens, S. Bordihn, A. Mohr, K. Petter, J.W. Müller, D.J.W. Jeong, R. Hao, T. Ravi
Epitaxy, n-Type c-Si, Solar Cell Efficiency
Subtopic: Silicon Solar Cell Improvements
Event: 31st European Photovoltaic Solar Energy Conference and Exhibition
Session: 2CV.4.34
1000 - 1002
ISBN: 3-936338-39-6
Paper DOI: 10.4229/EUPVSEC20152015-2CV.4.34
0,00 EUR
Document(s): paper


We present our latest results for screen printed solar cells on epitaxial kerfless wafers produced by Crystal Solar using its Direct Gas to WaferTM technology. This wafer manufacturing technique has the potential to decrease wafer cost significantly and the wafers have shown considerable advantages over conventional Cz solar wafers [1]. The starting epitaxial kerfless wafers are n-type silicon having an integrated epitaxial boron doped p+-silicon layer. These wafers, with an optimized built-in epitaxial boron doped p+-silicon layer as the rear side emitter, are processed applying the high efficiency process flow established for Hanwha Q CELLS Q.ANTUM technology to make p-type PERC cells [2]. The solar cells were processed in our Q.ANTUM production line including process adaptations to mono wafers. Front and rear contacts are screen printed using commercially available printing pastes and 3 bus bar layout. With this high efficiency Q.ANTUM process solar cell process sequence we achieve solar cell efficiencies up to 21.4 % (independently confirmed). In addition to the np+-epi wafer material we also processed p-type Cz material to p-PERC solar cells. The p-type Cz silicon reference shows in this process flow non-stabilized efficiencies up to 21 %. These solar cell results demonstrate a new path to solar cell efficiencies of 21.4 % and potentially >22 % by combination of simple and robust processing of all screen printed solar cells and epitaxial wafer growth with built-in doping layers.