(23a) Semiconducting Polythiophene Nanotubes by Template Wetting Nanofabrication

Here, the fabrication and characterization of semiconducting polythiophene (P3HT) nanotubes using template wetting nanofabrication is presented. Various types of template processing have proven to be effective means of producing nanoscale structures such as nano-tubules and nanowires from a broad range of materials. In particular, much research attention has been given to creating such structures from conducting polymers, mostly involving electrochemical deposition and electro-spinning techniques. Nanostructures of organic electronic materials fabricated using other templating methods have shown dramatically different, and in many cases better, electrical properties than their thin film counterparts. This work examines the properties of P3HT nanostructures formed using a novel methodology, template wetting. P3HT solutions were created by dissolving the polymer two different solvents, chloroform and xylene. P3HT nanotubes were created by wetting nanoporous alumina templates with 20 and 100 nm diameters. These nanowires were fitted with gold electrodes, creating ?hole-only? diodes. Effects of both solvent and tube diameter on electronic properties were examined. Current density ? voltage characteristics were measured and compared with changes in tube diameter and solvent. Significant improvement in hole mobility is observed in the nanotube devices as compared with thin-film devices. UV-Visible spectroscopy suggests significant narrowing of the valence band structure and an increased degree of molecular order in the nanostructured devices.