Aryl-Ethenyl-Substituted Diketopyrrolopyrrole Semiconductors with trans Configuration and Ultraclose π-Plane Stacking Distance

We present a new class of diketopyrrolopyrrole (DPP) derivatives, which comprise the ethenylidene linker that connects the DPP unit to aryls, such as thiophene ( TE-DPP ), furan ( FE-DPP ), and cyanothiophene ( CNTE-DPP ), respectively. The introduction of ethenylidene linkers led to extended π-conjugation length and enhanced intramolecular charge transfer, giving rise to prominent red shift in the visible region of the spectrum, low-lying lowest unoccupied molecular orbital (LUMO) level, and the narrow band gap. The single-crystal X-ray diffraction analysis reveals that the resulting compounds exhibit planar configurations with close π–π distances of 3.17 Å. Furthermore, these compounds exhibit one-dimensional arrangement, which benefits from intramolecular and intermolecular hydrogen bonds, facilitating short contact between donor and acceptor segments. Organic field-effect transistor (OFET) measurements reveal that TE-DPP and FE-DPP exhibit p-type transport behavior with maximum mobility of 0.05 and 0.18 cm 2 V –1 s –1, respectively. While CNTE-DPP exhibits ambipolar transport characteristics with electron and hole mobilities up to 0.13 and 0.24 cm 2 V –1 s –1, respectively. Our work demonstrates the potential of aryl-ethenyl-substituted diketopyrrolopyrroles ( ArE-DPPs ) as promising semiconducting materials for applications in organic electronic devices.