High-Mobility n-Type Organic Transistors Based on a Crystallized Diketopyrrolopyrrole Derivative

A new high‐performing small molecule n‐channel semiconductor based on diketopyrrolopyrrole (DPP), 2,2′‐(5,5′‐(2,5‐bis(2‐ethylhexyl)‐3,6‐dioxo‐2,3,5,6‐tetrahydropyrrolo[3,4‐c]pyrrole‐1,4‐diyl)bis(thiophene‐5,2‐diyl))bis(methan‐1‐yl‐1‐ylidene)dimalononitrile (DPP‐T‐DCV), is successfully synthesized. The frontier molecular orbitals in this designed structure are elaborately tuned by introducing a strong electron‐accepting functionality (dicyanovinyl). The well‐defined lamellar structures of the crystals display a uniform terrace step height corresponding to a molecular monolayer in the solid‐state. As a result of this tuning and the remarkable crystallinity derived from the conformational planarity, organic field‐effect transistors (OFETs) based on dense‐packed solution‐processed single‐crystals of DPP‐T‐DCV exhibit an electron mobility (μe) up to 0.96 cm2 V−1 s−1, one of the highest values yet obtained for DPP derivative‐based n‐channel OFETs. Polycrystalline OFETs show promise (with an μe up to 0.64 cm2 V−1 s−1) for practical utility in organic device applications. A new dicyanovinyl‐substituted diketopyrrolopyrrole (DPP)‐based small molecule, DPP‐T‐DCV, shows outstanding electron mobility (μe) in solution‐processed single‐crystal OFETs (SC‐OFETs). The molecular structure of DPP‐T‐DCV, SC‐OFETs device structure, and atomic force microscopy images of the film surface of the DPP‐T‐DCV crystal device are shown. SC‐OFETs exhibit μe as high as 0.96 cm2 V−1 s−1 with on/off current ratio of ≈105.