Synstematic Investigation of Molecular Orientation with Isomer-Free Quinoidal Polymers for Organic Field-Effect Transistors

Abstract

Quinoidal molecules have aroused great interest as a promising active layer for OFETs because of their unique advantages, which is beneficial for rigid and planar structure. In addition, they show the extended π-conjugation length resulting from the overlapping pz-orbitals. They can therefore induce the favorable charge transport path. However, since quinoidal molecules have the difficulty in purifying unavoidable geometric isomers during synthesis, studies on these molecules are relatively rare. We designed and synthesized the quinoidal monomer (QEDOT) with isomer-free. Finally, QEDOT was polymerized with spacers of thiophene, bithiophene and thienylene vinylene. In this study, As spacers are incorporated, quinoidal polymers showed the change of molecular orientation from bimodal and edge-on, resulting in the different charge transport property. The quinoidal polymers were systemically characterized with various measurements.