For bifacial Cu(In,Ga)Se 2 solar cells with submicron absorber thickness, an Al 2 O 3 -layer deposited by a simple, self-organized spray-pyrolysis process onto the transparent SnO 2 :F back-contact is used to increase open circuit voltage and thereby increase power conversion efficiency, especially for rear-illumination, indicating reduced charge carrier back-contact recombination. On non-passivated SnO 2 :F, a thin (10nm) Mo-layer improved the electrical back-contact properties, while on Al 2 O 3 -passivated SnO 2 :F, the solar cell performance was higher without Mo-modification. However, even with Momodification, the solar cell performance increased for Al 2 O 3 -passivated compared to non-passivated back-contacts demonstrating the benefit of the Al 2 O 3 -layer for bifacial solar cells with submicron Cu(In,Ga)Se 2 absorber layers.

Stabilized performance parameters of PV-modules are necessary for energy yield prediction as well as for the investigation of module degradation effects. The electrical parameters of thin-film modules show stabilization behaviors which are typical for the applied technology. However, this behavior is not satisfyingly understood yet. Different types of thin-film modules have been exposed to artificial irradiation and controlled temperatures in a climatic cabinet with a class B solar simulator for up to 330h. The modules have been connected to electronic loads to perform IV-curve measurements every 15 minutes and MPP-tracking between the measurements. The stabilization of the different parameters (Uoc, Isc, FF, Pmpp) has been analyzed using this data. Temperature correction was done with temperature coefficients which have been measured after a certain irradiation dose had been applied. Flasher-measurements have been used for confirmation of the DC-measurements after the relaxation of the modules after the continuous irradiation exposure was finished

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