Effect of surfactant conjugation on structure and properties of poly(3-hexylthiophene) colloids and field effect transistors

In this work, aqueous suspensions of poly(3-hexylthiophene) (P3HT) colloids were fabricated using three different surfactants with varied degrees of conjugation. The morphology, crystalline structure and optical properties of these colloids were characterized by scanning electron microscopy, wide angle X-ray diffractometry and UV–vis spectrometry, respectively. Results indicated that the morphology and crystalline were similar for all the colloids, while the optical properties and aggregation could be tuned by surfactant conjugation. Increasing conjugation in surfactant corresponded to increased chain order, conjugation length, and red-shifted absorbance spectrum in P3HT colloids. Field effect transistors (FETs) made from these colloids showed a hole mobility on the order of 10−3 cm2/Vs, also tunable by surfactant conjugation and comparable to FETs made from P3HT solution.