We report the processing conditions for inkjet-printed active layers of organic photovoltaic (OPV) devices comprising bulk-heterojunction blends of the low bandgap conjugated polymer poly[(4,4'-bis(2-ethylhexyl) dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(4,7-bis(2-thienyl)-2,1,3-benzothiadiazole)-5,5'-diyl] (Si-PCPDTBT) as well as poly[N-9'-hepta-decanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT) used as electron donors with [6,6]-phenyl-C71-butyric acid methyl ester (PC70BM) as electron acceptor. By controlling the inkjet printing processing conditions, we gain a significant improvement in device power conversion efficiency (PCE) to previously reported work using these materials. We obtain Si-PCPDTBT:fullerene and PCDTBT:fullerene-based inkjet-printed OPVs with power conversion efficiency of similar to 3% and similar to 4%, respectively. (C) 2014 Elsevier B.V. All rights reserved.