A planar electron acceptor for efficient polymer solar cellsElectronic supplementary information (ESI) available: Experimental details, density functional theory calculation details, TGA curves of IDT-2BR, J-V curves of the devices based on P3HT:IDT-2BR with different donor/acceptor ratios, data of the OSCs based on P3HT : IDT-2BR blends (1 : 0.6, w/w) with 3% CN with various active layer thicknesses, J-V and IPCE curves of the device based on P3HT : PC61BM (1 : 1, w/w), SCLC device characterist

A novel planar acceptor IDT-2BR was designed and synthesized. Polymer solar cells (PSCs) based on P3HT:IDT-2BR blended films gave power conversion efficiencies of up to 5.12%, which are much higher than that of PC 61 BM-based control devices (3.71%) and the highest values reported for P3HT-based fullerene-free PSCs. Polymer solar cells (PSCs) based on blended films of a novel planar acceptor and P3HT gave power conversion efficiencies of up to 5.12%, which are much higher than that of PC 61 BM-based control devices (3.71%) and the highest values reported for P3HT-based fullerene-free PSCs.