Excitons in semiconducting carbon nanotubes: diameter-dependent photoluminescence spectra

Semiconducting single-walled carbon nanotubes are one-dimensional (1D) quantum nanostructures and their unique optical responses arise from stable 1D excitons with huge binding energies. Here we review recent studies on optical properties of semiconducting carbon nanotubes. The diameter dependence of luminescence spectra and dynamics are revealed by single-nanotube spectroscopy and time-resolved optical spectroscopy. Short-range Coulomb interactions play a crucial role in energy structures of dark, triplet, and charged excitons. Enhanced exciton-exciton interactions in 1D semiconductor nanostructures determine nonlinear optical responses. We present generic configurations of neutral and charged excitons and discuss exciton optics of single-walled carbon nanotubes.