 Photovoltaics
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GALVANIC GRAIN BOUNDARY CONTACTS ON MULTICRYSTALLINE
SILICON SOLAR CELLS
Rita Ebner1, Maria Raith1,
Viktor Schlosser2 and Johann Summhammer1
Atominstitut der
Österreichischen Universitäten, A-1020 Wien, Stadionallee
2, Austria.
Institut für Materialphysik der Universität
Wien, A-1090 Wien, Strudlhofgasse 4, Austria.
Email: rita.ebner@ati.ac.at,
Homepage of solar cells group at Atominstitut: www.ati.ac.at/~summweb
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- ABSTRACT
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We present new results of putting the metallic front contact pattern
of multicrystalline silicon solar cells over and along grain
boundaries (Grain Boundary Oriented Finger grid - GBOF-grid). In a
previous study the contacts were formed by automated grain boundary
detection and writing of the contact pattern with ordinary screen
printing paste. Now we used a galvanic method with nickel as a
diffusion barrier and silver as the conductor, in view of a possible
application in laser grooved buried contact cells. This gave very
low contact and series resistances. Using Baysix©
100x100-wafers, we compared so called ON-cells, which received the
GBOF-grid so that the front contacts ran mostly along grain
boundaries, OFF-cells, where the same pattern was used but was
rotated by 90° to give only little coverage of grain boundaries,
STD-cells with the H-pattern of most commercial silicon solar cells,
and GRD-cells with a geometric rectangular grid pattern. With the
same total shading on all four kinds of patterns, a clear advantage
for the grain boundary contacted ON-cells is found, exceeding the
results of the previous study. Under approximately standard
conditions, ON-cells gave at least 5 per cent more power than the
STD-cells and in some batches over 10 per cent more. Their
performance improvement over the OFF- and the GRD-cells shows
similar values
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Keywords:
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1, multi-crystalline - 2, grain - 3, galvanic contacting