Synthesis and photovoltaic properties of acceptor materials based on the dimerization of fullerene C60 for use in efficient polymer solar cells.

We demonstrate that dimeric fullerene derivatives work as an excellent n-type material for polymer solar cells in combination with P3HT or PTB7, showing the best PCE of 3.3% or 6.1%, respectively. The device performance was influenced by the position of the two C60 moieties linked together.