Titel:

Explanation of high solar cell diode factors by nonuniform contact resistance


Auteur(s):



Gepubliceerd door:

Publicatie datum:

ECN
Zonneenergie

142004


ECN publicatienummer:

Publicatie type:

ECNRX04009

Artikel wetenschap tijdschrift


Aantal pagina's:


16


Gepubliceerd in: Progress in Photovoltaics: Research and Applications (John Wiley & Sons Ltd.), , 2005, Vol.13, p.316.
Samenvatting:
The current densityvoltage (JV) curve that characterises
the performance of a solar cell is often 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 JV
curve of a high m solar cell using local contact resistances measured
with the socalled Corescan and the cell?s resistanceless JV curve
as measured with the socalled SunsV_{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.
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