(Invited) Combining Absorption, Wavelength-Dependent Raman and Fluorescence-Excitation Spectroscopy with High-Resolution Transmission Electron Microscopy for Determining the Chiral Purity of Sorted SWCNT Samples

Single-wall carbon nanotubes (SWCNTs) possess unique electronic and optical properties that depend strongly on their exact chiral structure. Recent progress in the structure sorting of specific SWCNT chiralities, with increasing chiral purity[1], demands an effective characterization methodology to be developed to accurately determine the chiral composition of any SWCNT chirality. Very often, optical spectroscopy is used to assess the chiral composition of a sample, but absorption cross-sections, PL quantum efficiencies and Raman cross-sections are all depending on the exact chiral structure,[2] and can be strongly influenced by other factors such as the specific internal and external environment of the SWCNTs.[3] In this work, we systematically compare the chirality distribution obtained from 3 different optical spectroscopic techniques, i.e. absorption, wavelength-dependent Raman and fluorescence-excitation spectroscopy with the chirality distribution obtained from high-resolution transmission electron microscopy for both chirality-sorted and unsorted SWCNT samples. This combined approach demonstrates the importance of using a multi-technique characterization strategy for a reliable determination of SWCNT chirality distribution.[4] [1] J.A. Fagan, Nanoscale Adv. 1, 3307 (2019) and references therein [2] V.N. Popov, Nano Lett. 4, 1795 (2004) [3] S. Cambré et al, Angew. Chem. – Int Ed. 50, 2764 (2011); ACS nano 6, 2649 (2012) [4] A. Castan et al, Carbon 171, 968 (2021)