An H-shaped, small molecular non-fullerene acceptor for efficient organic solar cells with an impressive open-circuit voltage of 1.17 V

A bifluorenylidene-functionalized, H-shaped, small molecular non-fullerene electron acceptor, 6,6′,6′′,6′′′-([9,9′-bifluorenylidene]-2,2′,7,7′-tetrayltetrakis(thiophene-5,2-diyl))tetrakis(2,5-bis(2-ethylhexyl)-3-(thiophen-2-yl)-2,5-dihydrop yrrolo[3,4-c]pyrrole-1,4-dione) (coded as H1), which used diketopyrrolopyrrole as terminal functionalities, was designed, synthesized and characterized. H1 displayed a very high optical absorption coefficient, good solubility and thermal stability, promising optoelectronic properties, and high electron mobility, and afforded an encouraging efficiency of 5.42% when paired with the archetypal electron donor poly(3-hexylthiophene).