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Explanation of high solar cell diode factors by nonuniform contact resistance
Author(s) -
van der Heide A. S. H.,
Schönecker A.,
Bultman J. H.,
Sinke W. C.
Publication year - 2005
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.556
Subject(s) - equivalent series resistance , saturation current , contact resistance , solar cell , diode , materials science , saturation (graph theory) , voltage , mechanics , condensed matter physics , physics , mathematics , optoelectronics , electrical engineering , composite material , engineering , layer (electronics) , combinatorics
The current density–voltage ( J – V ) curve that characterises the performance of a solar cell is often extra rounded, resulting in reduced efficiency. When fitting to the standard one‐dimensional models, it is often found that the rounding cannot be fitted by the series resistance only. In these cases, the diode factor m or the depletion region saturation current density J 0DR (depending on the model used) is increased. This behaviour could not be explained so far; this paper discusses if a nonuniform contact resistance of the front side metallisation leads to an increase of m or J 0DR . The theoretical part of the investigation is the simulation of the curve for a cell with two regions with different contact resistance. It was found indeed that m or J 0DR is increased, while the series resistance is not increased as much as expected. The experimental part was the calculation of the J – V curve of a high‐ m solar cell with local contact resistances measured with the so‐called Corescan and the cell's resistanceless J – V curve as measured with the so‐called Suns‐ V oc method. The calculated curve approximated the actual curve quite well, demonstrating in practice that high diode factors can be explained by nonuniform contact resistance. Copyright © 2004 John Wiley & Sons, Ltd.