High-Speed Directed Self-Assembly for Uniaxially Oriented Polymer Semiconductor Thin Films

Abstract

Efficient charge transport in polymer semiconductors relies on unidirectional chain orientation to overcome structural disorders and facilitate quasi-two-dimensional charge delocalization. In this study, we present a scalable approach for fabricating highly oriented thin films of a regioregular donor-acceptor polymer semiconductor on nanogrooved silicon dioxide substrates using an off-center spin coating (OCSC) method. By systematically adjusting the groove alignment, binary solvent composition, and OCSC parameters, we achieved polarization dichroic ratios exceeding 8.0. These results were confirmed by polarized ultraviolet-visible-near-infrared absorption spectroscopy and grazing-incidence wide-angle X-ray diffraction. The resulting thin films exhibited strongly anisotropic charge transport, with hole and electron mobilities surpassing those of control devices by an order of magnitude. The optimized thin films exhibited balanced ambipolar charge transport (similar to 4.5 cm2 V-1 s-1) and enabled the realization of complementary metal-oxide-semiconductor inverters with voltage gains up to similar to 53. These findings establish nanogroove-assisted OCSC as a practical and scalable approach for fabricating unidirectionally oriented polymer semiconductor thin films for high-performance plastic electronics.