The role of terpineol additive in poly(3-hexylthiophene) films for enhanced performance of electrolyte gated transistors

Abstract

Solution-processed electrolyte-gated transistors (EGTs) offer several advantages, including low operating voltage, high drain current levels, and versatile processability. For EGTs utilizing polymer semiconductors, the device's electrical properties are significantly influenced by the surface morphology and microstructure of the polymer film. One way to improve the film properties is employing solvent additive to polymer precursor solution. Terpineol has been a widely used additive in poly (3-hexylthiophene) (P3HT) precursor solution. In this work, we systematically investigated the effect of terpineol additive on P3HT film morphology and electrical performance of EGTs. The P3HT film, formed via spin-coating from this modified precursor solution, exhibited a dense and continuous morphology. Transistors fabricated with this solvent additive demonstrated improved electrical performance, with mobility increasing from 1.22 to 1.62 cm²V⁻¹s⁻¹ for a 1.54 % additive content. This investigation provides insights into the influence of high boiling point additives on the morphology of polymer semiconductor films and serves as a guide to aid in the use of such additives within EGTs and other electrical devices.