Spectroscopic characterization of photolytically generated radical ion pairs in single-wall carbon nanotubes bearing surface-immobilized tetrathiafulvalenes

We succeeded in establishing for the first time a conclusive spectroscopic signature for reduced single-wall carbon nanotubes (SWNT), which evolves from electron donor−acceptor interactions between SWNT and electron-donating π-extended tetrathiafulvalene (exTTF). In particular, π−π interactions were employed to anchor the electron donor to the surface of SWNT. New conduction band electrons, injected from photoexcited exTTF, shift the transitions that are associated with the van Hove singularities to lower energies.