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Investigation of UV-Induced Degradation of Different Types of WPVS Reference Solar Cells
I. Kröger, J. Hohl-Ebinger, S. Brachmann, S. Winter
Calibration, Degradation, Encapsulation, Durability, Characterisation, Characterization
Operation, Performance, Reliability and Sustainability of Photovoltaics
Subtopic: PV Cells and Modules
Event: 32nd European Photovoltaic Solar Energy Conference and Exhibition
Session: 5BV.4.34
2277 - 2281
ISBN: 3-936338-41-8
Paper DOI: 10.4229/EUPVSEC20162016-5BV.4.34
0,00 EUR
Document(s): paper


Calibrated World Photovoltaic Scale (WPVS) reference solar cells are widely used for calibrating the irradiance of solar simulators as well as the determination of spectral mismatch correction factors. WPVS reference solar cells should provide long term stability of the short circuit current under standard test conditions < 0.3% over typical recalibration intervals of 1-2 years. The UV-irradiance of the utilized light sources (natural sunlight or solar simulators) can lead to degradation effects either in the solar cell itself or in the encapsulant. In this study different types of WPVS reference solar cells were exposed to elevated UV-irradiance in order to investigate the long term stability of the devices over a period of several hundreds of hours of permanent irradiation. Prior and after the UVexposure high precision differential spectral responsivity (DSR) calibrations were performed in order to investigate the impact of the UV-aging on the spectral responsivity and hence the short circuit current of the individual devices. In order to identify small relative changes < 0.2% of the spectral responsivity a DSR-facility is needed with very high reproducibility. This could be realized at the DSR and Laser-DSR facilities at PTB. Nine different types of reference solar cells were prepared by Fraunhofer ISE. They were developed to spectrally match different solar cell technologies. The BG38 and BG40 filtered devices should spectrally match a-Si solar cells, the OG590 and RG610 filtered devices should spectrally match μ-Si solar cells and the GaAs solar cell should spectrally match CdTe solar cells. The three unfiltered c-Si devices show different spectral responsivity in the IRregion. In conclusion these reference devices represent a thoroughly set covering all possible spectral responsivities needed in the PV-calibration and testing community.