Synthetic control over the binding configuration of luminescent sp3-defects in single-walled carbon nanotubes

The controlled functionalization of single-walled carbon nanotubes with luminescent sp(3)-defects has created the potential to employ them as quantum-light sources in the near-infrared. For that, it is crucial to control their spectral diversity. The emission wavelength is determined by the binding configuration of the defects rather than the molecular structure of the attached groups. However, current functionalization methods produce a variety of binding configurations and thus emission wavelengths. We introduce a simple reaction protocol for the creation of only one type of luminescent defect in polymer-sorted (6,5) nanotubes, which is more red-shifted and exhibits longer photoluminescence lifetimes than the commonly obtained binding configurations. We demonstrate single-photon emission at room temperature and expand this functionalization to other polymer-wrapped nanotubes with emission further in the near-infrared. As the selectivity of the reaction with various aniline derivatives depends on the presence of an organic base we propose nucleophilic addition as the reaction mechanism. Covalent functionalization of single-walled carbon nanotubes with luminescent sp(3)-defects generally produces a variety of binding configurations and emission wavelengths. The authors propose a base-mediated nucleophilic functionalization approach to selectively achieve configurations for E-11* and E-11*(-) or purely E-11*(-) defect emission.

Automated summary

The study introduces the potential of employing single-walled carbon nanotubes with luminescent defects as quantum-light sources in the near-infrared. A simple reaction protocol is proposed to create only one type of luminescent defect in nanotubes with longer photoluminescence lifetimes.