This study involves the development of two new small molecules comprising a diketopyrrolopyrrole (DPP) core flanked with donor units of triphenylamine (TPA-DPP-TPA) and fluorine (FL-DPP-FL) for application in bulk heterojunction (BHJ) organic solar cells (OSCs). The OSCs based on FL-DPP-FL and PC71 BM exhibited a PCE of 1.73%, compared to 1.45% for that obtained from devices of TPA-DPP-TPA. The morphological studies reveal that the enhancement in OSCs of FL-DPP-FL is mainly attributed to the improved nanoscale film morphology of the FL-DPP-FL:PC71 BM blend, which promoted the formation of smaller domains and greater donor-acceptor interpenetrated networks within the active layer. (C) 2015 Elsevier B.V. All rights reserved.