Naphthalene diimide-based non-fullerene acceptors flanked by open-ended and aromatizable acceptor functionalitiesElectronic supplementary information (ESI) available: Experimental details, synthetic procedures, theoretical optical absorption, PESA, CV, TGA, DSC, IPCE and experimental spectra. See DOI: 10.1039/c7cc06369e

Herein we present the design, synthesis and characterization of two novel, naphthalene diimide (NDI) core-based non-fullerene acceptors, N5 and N6 , comprising respectively 2-methoxyethyl-2-cyanoacetate and cyanopyridone acceptor functionalities at the terminals. The influence of terminal units on optoelectronic and photovoltaic properties was studied. The target chromophore bearing cyanopyridone acceptor units ( N6 ) afforded a power conversion efficiency of 6.10% when paired with the conventional donor polymer poly(3-hexylthiophene), a result that is the highest for the NDI core-based non-fullerene acceptors. Herein we report synthesis and characterization of two NDI core-substituted non-fullerene acceptors, N5 and N6 , the chromophore ( N6 ) bearing cyanopyridone acceptor units afforded a PCE of 6.10%.