Royal Society of Chemistry, RSC Advances
DOI: 10.1039/c6ra01558a
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A novel, solution-processable non-fullerene electron acceptor, 6,6'-((9-(heptadecan-9-yl)-9H-carbazole-2,7-diyl)bis (thiophene-5,2-diyl))bis(2,5-bis(2-ethylhexyl)-3-(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione) (coded as N7), based on central carbazole and terminal diketopyrrolopyrrole building blocks was designed, synthesized and characterized. N7 displayed excellent solubility, thanks to its design envision allowing incorporation of numerous lypophilic chains, thermal stability, and afforded 2.30% power conversion efficiency with a high open-circuit voltage (1.17 V) when tested with the conventional donor polymer poly(3-hexylthiophene) in solution-processable bulk-heterojunction devices. To our knowledge, not only N7 is the first reported chromophore based on carbazole and diketopyrrolopyrrole functionalities but the open-circuit voltage reported here is among the highest values for a single junction bulk-heterojunction device that has been fabricated using simple device architecture, reproducible outcome and with no special treatment.