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1989
Conference Paper
Titel
New approaches to reduce uncertainty in solar cell efficiency measurements introduced by non-uniformity of irradiance and poor FF-determination
Abstract
Non-uniformity of the irradiance in the test plane of a solar simulator leads to errors in the determination of the incident radiation power, hence in the efficiency if reference cell and test cell are not exposed to exactly the same irradiance pattern. To overcome this uncertainty in solar cell calibration, we developed a correction procedure for the incident power using a scanning device for the measurement of the spatial uniformity. In this paper the procedure and experimental results for 10 x 10 square centimeter solar cells are presented and it is shown that the uncertainty is significantly reduced. The uncertainty in the fill factor determination of bare large area solar cells is high because of the large number of error sources such as type and position of the contacting probes, contact resistance, temperature, software. We tried to quantify these influences by making experiments with a 10 x 10 square centimeter solar cell. We developed a method to make a 4 probe meausrement of the contact resistance of a Kelvin probe, thus reducing the uncertainty due to contact resistance to a minimum. Our results show how uncertainty in fill factor determination can be reduced.