Absolute Quantification of sp3Defects in Semiconducting Single-Wall Carbon Nanotubes by Raman Spectroscopy

The functionalization of semiconducting single-wall carbon nanotubes(SWCNTs) with luminescent sp3defects creates red-shifted emission features in the near-infrared and boosts their photoluminescence quantum yields (PLQYs). While multiplesynthetic routes for the selective introduction of sp3defects have been developed, a convenientmetric to precisely quantify the number of defects on a SWCNT lattice is not available. Here,we present a direct and simple quantification protocol based on a linear correlation of theintegrated Raman D/G+signal ratios and defect densities as extracted from PLQYmeasurements. Corroborated by a statistical analysis of single-nanotube emission spectra atcryogenic temperature, this method enables the quantitative evaluation of sp3defect densitiesin (6,5) SWCNTs with an error of +/- 3 defects per micrometer and the determination ofoscillator strengths for different defect types. The developed protocol requires only standardRaman spectroscopy and is independent of the defect configuration, dispersion solvent, andnanotube length.

Automated summary

Researchers have proposed a direct quantification protocol based on a linear correlation that can accurately assess the defect density on the lattice of single-wall carbon nanotubes (SWCNTs) and determine the oscillator strengths of different defect types.