Enhancement of organic field-effect transistor performance via precision molecular alignment of a P4T2F-HD-based conjugated polymer

This study conducts a detailed exploration of how the orientation of molecules affects the efficiency of organic field-effect transistors (OFETs), with a particular focus on a new conjugated polymer, P4T2F-HD. The study examines the fabrication of both large-scale, anisotropically oriented thin films and non-oriented, isotropic thin films of P4T2F-HD through two separate approaches: the Unidirectional Film Transfer Method (UFTM) for oriented films and spin-coating for isotropic films. Results indicate that UFTM notably excels in directing the molecular alignment of P4T2F-HD across extensive areas, thereby creating anisotropic thin films, whereas spin-coating yields isotropic thin films lacking specific orientation. Further investigation into the properties of these films through various analytical techniques sheds light on the role of molecular orientation in influencing their electronic characteristics. OFETs fabricated with anisotropically oriented P4T2F-HD films exhibit markedly improved performance, characterized by higher charge carrier mobility and enhanced electrical stability, in comparison to their isotropic counterparts. The study evidences that the directional arrangement of macromolecules plays a pivotal role in OFETs functionality, with UFTM-derived films demonstrating a significant leap in field-effect mobility—showing an over 100-fold improvement over spin-coated films. This boost is linked to the effective charge transmission along the polymer chains, enabled by precise molecular alignment.