Mechanism for optical activation of dark spin-triplet excitons in hydrogenated single-walled carbon nanotubes

摘要

We have theoretically studied the optical properties of hydrogenated single-walled carbon nanotubes and propose an underlying mechanism for the optical activation of dark spin-triplet excitons. We investigated spin-flipping effects by hydrogen adatoms on exciton states by solving the Bethe-Salpeter equation using the tight-binding approximation. The calculated absorption spectra show a satellite peak that originates from the triplet dark exciton in addition to the main peak of the bright singlet exciton. This study provides a microscopic mechanism for the origin of the satellite peak observed in the recent photoluminescence spectroscopy.