Effects of Thermal Annealing and Solvent Annealing on the Morphologies and Properties of Poly(3-hexylthiophene) Nanowires

In recent years, poly(3-hexylthiophene) (P3HT) nanowires have attracted great interest because of their unique physical and electronic properties. The annealing effects on the properties and morphologies of P3HT nanowires, however, are still not fully understood. In this work, the effects of thermal annealing and solvent annealing on the morphologies and crystallinities of P3HT nanowires prepared by the whisker method are studied. P3HT is first dissolved in heated p-xylene, followed by a cooling process to room temperature, and P3HT nanowires are formed by self-assembly. The crystallinities of the P3HT nanowires are observed to increase by both thermal annealing and solvent annealing, as confirmed by differential scanning calorimetry and X-ray diffraction. The device performances of organic field-effect transistors based on the annealed nanowires are also examined. After annealing, an enhancement of the charge mobility by one order is observed.