Vertical confinement and interface effects on the microstructure and charge transport of P3HT thin films

Abstract Using X‐ray diffraction‐based pole figures, we present quantitative analysis of the microstructure of poly(3‐hexylthiophene) thin films of varying thicknesses, which allows us to determine the crystallinity and microstructure at the semiconductor‐dielectric interface. We find that the interface is approximately one fourth as crystalline as the bulk of the material. Furthermore, the use of a self‐assembled monolayer (SAM) enhances the density of interface‐nucleated crystallites by a factor of ∼20. Charge transport measurements as a function of film thickness correlate with interface crystallinity. Hence, we establish the crucial role of SAMs as nucleating agents for increasing carrier mobility in field‐effect devices. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013