Photo-induced charge transfer in fullerene–oligothiophene dyads – A quantum-chemical study

The excited states of fullerene–oligothiophene dyads were studied by quantum-chemical methods in respect of their theoretical suitability as solar-cell materials. Compared to the constituents a significant extension of the absorption spectra to the red has been found caused by optically excitable charge transfer states. These states seem to be responsible for the low energy conversion efficiency of fullerene–oligothiophene dyads in photovoltaic devices.