Synthesis of long-chain polythiophene inside carbon nanotubes

Abstract

We developed the synthesis of one-dimensional polythiophenes inside single-wall carbon nanotubes (SWCNTs). Direct vapor-phase reaction with dibromobithiophenes provided long-conjugated polythiophenes through dehalogenative polymerization in the cavities of SWCNTs. Tethering of the large number of thiophene units was confirmed by optical absorption measurement and high-resolution transmission electron microscopic (HR-TEM) observation. Raman spectroscopy indicated that restricted one-dimensional inner space of SWCNTs enables s-trans coplanar conformation of thiophene moieties. We also revealed a weak p-doping of metallic SWCNTs selectively occurred by bromine molecules, which were generated during the synthesis of polythiophenes.