Acceptor polymers for photovoltaic applications were synthesized by grafting fullerene C(60) onto polystyrene. The quality of the reaction was verified by various analytical techniques after each of the three steps of the reaction: nuclear magnetic resonance, infrared and UV-visible spectroscopies, and thermo-gravimetric analysis. In order to determine the optimal amount of C(60), a series of polymers were prepared containing from 4 to 59 vol.% of fullerene. The optical (absorption, optical gap energy) and electrical (electron mobility, conductivity) properties have been measured. A percolation threshold at around 4 vol.% was identified for both conductivity and mobility measurements. This provides the lowest amount of C(60) required for solar cells applications. (C) 2011 Elsevier Ltd. All rights reserved.