Planar-orientation polycrystalline thin film of liquid-crystalline organic semiconductor by template-directed self-assembly

Abstract

We fabricated planar-orientation crystalline thin films of organic semiconductors, in which molecules sit parallel, i.e., “face-on”, on the substrate and favor vertical charge transport. Thanks to molecular orientation that is sensitive to surface properties and the self-organization of liquid crystals, planar-orientation crystalline thin films can be prepared by simply cooling a smectic liquid-crystalline organic semiconductor from isotropic temperature with the aid of a poly(vinyl alcohol) (PVA) microtemplate. The molecular orientation of crystalline thin films was investigated by polarized optical microscopy (POM) and X-ray diffraction (XRD) analysis, and the current–voltage characteristics of the films were studied in a diode configuration. The results showed high potential for device applications.