Effects of concentrated sunlight on organic photovoltaics

We report the effects of concentrated sunlight on key photovoltaic parameters and stability of organic photovoltaics (OPV). Sunlight collected and concentrated outdoors was focused into an optical fiber and delivered onto a 1 cm(2) bulk-heterojunction cell. Sunlight concentration C was varied gradually from 0.2 to 27 suns. Power conversion efficiency exhibited slow increase with C that was followed by saturation around 2% at C=0.5-2.5 suns and subsequent strong reduction. Possible OPV applications in stationary solar concentrators (C < 2 suns) are discussed. Finally, experiments at C=55-58 suns demonstrated potential of our approach for accelerated studies of light induced mechanisms in the OPV degradation.