Solvation-induced one-dimensional polarons and electron transfer.

When a one-dimensional (1D) semiconductor nanostructure is immersed in a sluggish polar solvent, fluctuations of the medium may result in the appearance of localized electronic levels inside the band gap. An excess charge carrier can occupy such a level and undergo self-localization into a large-radius adiabatic polaron surrounded by a self-consistent medium polarization pattern. Within an appropriately adapted framework of the Marcus theory, we explore the description and qualitative picture of thermally activated electron transfer involving solvation-induced polaroniclike states by considering transfer between small and 1D species as well as between two 1D species. Illustrative calculations are performed for tubular geometries with possible applications to carbon nanotube systems.

Optical absorption from solvation-induced polarons on nanotubes.

When an excess charge carrier is added to a one-dimensional (1D) wide-band semiconductor immersed in a polar solvent, the carrier can undergo self-localization into a large-radius adiabatic polaron. We explore the local optical absorption from the ground state of 1D polarons using a simplified theoretical model for small-diameter tubular structures. It is found that about 90% of the absorption strength is contained in the transition to the second lowest-energy localized electronic level formed in the polarization potential well, with the equilibrium transition energy larger than the binding energy of the polaron. Thermal fluctuations, however, can cause a very substantial--an order of magnitude larger than the thermal energy--broadening of the transition. The resulting broad absorption feature may serve as a signature for the optical detection of solvated charge carriers.