High-Performing Thin-Film Transistors in Large Spherulites of Conjugated Polymer Formed by Epitaxial Growth on Removable Organic Crystalline Templates

Abstract

Diketopyrrolopyrrole (DPP)-based conjugated polymer <b>PDTDPPQT</b> was synthesized and was used to perform epitaxial polymer crystal growth on removable 1,3,5-trichlorobenzene crystallite templates. A thin-film transistor (TFT) was successfully fabricated in well-grown large spherulites of <b>PDTDPPQT</b>. The charge carrier mobility along the radial direction of the spherulites was measured to be 5.46–12.04 cm² V^–1 s^–1, which is significantly higher than that in the direction perpendicular to the radial direction. The dynamic response of charge transport was also investigated by applying a pulsed bias to TFTs loaded with a resistor (∼20 MΩ). The charge-transport behaviors along the radial direction and perpendicular to the radial direction were investigated by static and dynamic experiments through a resistor-loaded (RL) inverter. The RL inverter made of <b>PDTDPPQT</b>-based TFT operates well, maintaining a fairly high switching voltage ratio (<i>V</i>_out^ON/<i>V</i>_out^OFF) at a relatively high frequency when the source-drain electrodes are aligned parallel to the radial direction