Solar cells based on poly(3-alkyl)thiophenes and [60]fullerene: a comparative study

Photovoltaic cells made, at ambient conditions, from blends of regioregular poly(3-alkylthiophenes) and soluble fullerene derivatives are compared. It is shown that the cell performance is affected by the length of the donor side-chain, as it occurs in devices based on pure polythiophenes. The highest value of power conversion efficiency (0.84%) were obtained by using poly(3-hexylthiophene) and a fullerene concentration of 33-40% by weight. We anticipate a significant further improvement in power conversion efficiency upon a mild thermal treatment of the cells.