Color centers in single-walled carbon nanotubes attract interest because of their single-photon emission at room temperature in the telecom range . However, the lack of vapor-phase reaction route for forming color centers hinders the use of the excellent optical properties of air-suspended carbon nanotubes. We herein demonstrate the functionalization of air-suspended carbon nanotubes using iodobenzene as a precursor. The chemical reaction procedure is rationally designed to maintain the suspended structure and fluorescent properties of carbon nanotubes. The formed phenyl group serves as a color center and exhibits localized exciton emission peaks E11* and E_(11)*- in addition to the free exciton emission peak E_(11). We characterize over 12 different chiralities, covering nanotubes with diameters d ranging from 0.981 to 1.29 nm, to elucidate the reactivity and optical property of the color centers. We find that the reactivity of iodobenzene scales as 1/d, where the inherent strain on the curvature of nanotubes promotes the reaction. The trapping potential of E11* and E_(11)*- are both close to the singlet-triplet splitting. The minimum value of g~((2)((0) in the photon correlation verifies the photon antibunching at the color centers. These findings should lead to further development of quantum photon sources that utilize color centers in carbon nanotubes.
展开▼
