Process optimization for the fabrication of PCPDTBT/PCBM-based bulk heterojunction solar cells using polymers synthesized by Suzuki coupling is described. The relationship between the chem. purity of the polymers and the performance of the devices was examd. and by using a combination of OFET, OPV and hole-only devices, the best polymer purifn. technique identified. The purified polymers were used to optimize the fabrication of solar cells by varying the donor-acceptor blend ratio, the film thickness, the drying conditions and the concn. of the dithiol process additive. [on SciFinder (R)] ; 52 Electrochemical, Radiational, and Thermal Energy Technology School of Electronics,Bangor University,Bangor, Gwynedd, Wales,UK. Journal; Online Computer File