Four new D-A type copolymers with 2D-conjugated side-chain identified PfToBT, PbToBT, PfTDPP and PbTDPP, containing two acceptors 4,7-dithien-2-yl-benzo[c][1,2,5]thiadiazole (DTBT), and diketopyrrolopyrrole (DPP) linked by thiophene donors, are obtained using Pd-catalyzed Stille-coupling reaction. These polymers show a broad visiblenear-infrared absorption band (E-g 5 1.79-1.66 eV) and possess a relatively low-lying HOMO level at 25.34 to 25.12 eV. All the polymer: PC70BM blend films showed edge-on structure and have similar dp-spacing values. According to the structure of conjugated side-chain, the vertical distributions of polymer chains and PC70BM within the BHJ (bulk heterojunction) were different. When DPP used as an acceptor, conjugated side chains of the polymer coexisted with PC70BM in same position. The BHJ film prepared from PfToBT, PbToBT had a discontinuous network between polymer and PC70BM, whereas films from PfTDPP and PbTDPP formed continuous and evenly distributed network between them. This optimized vertical morphology promotes hole transport along respective pathways of polymers and fullerenes in the vertical direction, leading to high J(SC). PbTDPP shows PCE up to 2.9% (Jsc of 9.4 mA/cm(2), Voc of 0.68 V, and FF of 0.44). (C) 2016 Wiley Periodicals, Inc.