A Twisted Perylene Semiconductor

Significance

Principles of crystal engineering have been applied to the synthesis and self-­assembly of an n-channel organic semiconductor. Efficient charge-carrier transport in π-conjugated semiconductors is often inhibited by the predisposition of extended aromatic molecules to stack ‘edge-to-face’ in the solid state. To circumvent this problem the authors subjected perylene to robust chlorination conditions in order to generate the octachloro derivative 1. The torsion induced by halogenation is clearly observed in the solid state (a). As a result of this twisted conformation and the regular hydrogen bonding between adjacent diimide units, the aromatic units π-stack ‘face-to-face’ in a close-packed ‘brickstone’ arrangement (b, c). Thin-film devices based on this material exhibited air-stable operation with a charge carrier mobility as high as 0.82 cm^²V^-¹s^-¹.