P3HT-fiber-based field-effect transistor: Effects of nanostructure and annealing temperature

Abstract

Poly(3-hexylthiophene) nanofibers were prepared under ambient conditions and applied in organic field-effect transistors (FETs). Top-contact FETs with spin-coated and nanofiber-based layers were fabricated to compare their transport performance. It was found that the nanofiber FET shows a higher performance than the spin-coated one. The effects of annealing on the device performance of the nanofiber FET were also investigated from room temperature to 120 °C. The key performance characteristics of the nanofiber FET, such as carrier mobility and ON/OFF ratio, were improved by low-temperature annealing up to 80 °C. However, they were degraded by high-temperature annealing at 120 °C. The modulation of the surface morphology observed by atomic force microscopy is consistent with the change in device performance. The results of the correlation analysis of the mobility, hysteresis, and OFF current indicate that the change in FET performance is due to the disappearance of nanofiber interspaces and the removal of adsorbed molecules by temperature-controlled annealing. © 2014 The Japan Society of Applied Physics.