Supramolecular structures fabricated through the epitaxial growth of semiconducting poly(3-hexylthiophene) on carbon nanotubes as building blocks of nanoscale electronics†
Semiconducting conjugated polymers such as (3-hexylthiophene) (P3HT) and carbon nanotubes are attractive for applications that include field-effect transistors and photovoltaic devices. In these applications, the control of structure, morphology, and alignment of polymer chains is important from the perspective of charge transport and optical properties. In this regard, a novel solution-based nucleation approach involving direct epitaxial nucleation of nanofibers of the poly(3-hexylthiophene) (P3HT) polymer on carbon nanotubes (CNTs) leading to supramolecular structure is demonstrated. The supramolecular structure of P3HT on CNTs is characterized by nucleation of oriented precursors of P3HT on CNTs by an epitaxial mechanism, onto which high density transcrystalline ∼800–1000 nm long nanofibrils of P3HT with a thickness of ∼2–3 nm are nucleated in a periodic manner. The nanoscale structure of epitaxially grown P3HT nanofibrils exhibits optical and photoluminescence characteristics. The UV-vis spectroscopy study of the fabricated structure suggests a combination of π–π electronic transition and a strong lattice vibration in the conjugated polymer chains. Furthermore, the supramolecular structure is envisaged to comprise an accumulating thread for charge transport, onto which nanometer thick long fibrils are assembled in a periodic configuration with strong potential for organic–inorganic optoelectronic devices. In conclusion, the described approach enables fabrication of supramolecular structure on carbon nanotube-based electrodes, making it attractive for functional devices.