The helicity sorting
and optical resolution of single-walled carbon nanotube (SWNT) derivatives
were investigated to elucidate their fundamental properties and to
fully understand their application scope. Herein, the helicity sorting
and optical resolution of functionalized SWNTs (SWNTs-xylyl), which
were prepared by reductive alkylation using 1,2-bis(bromomethyl)benzene,
were achieved for the first time via gel chromatography using an agarose
gel as the stationary phase. By applying a stepwise elution, three
surfactant types (6,4) SWNTs-xylyl, (11,–5) SWNTs-xylyl, and
(6,5) SWNTs-xylyl were successfully separated and characterized. The
circular dichroism spectra of (11,–5) SWNTs-xylyl and (6,5)
SWNTs-xylyl were mirror images of each other along the abscissa, confirming
the successful enantiomeric separation of these functionalized SWNTs.
Both of the SWNTs-xylyl enantiomers showed red-shifted near-infrared
(NIR) photoluminescence (PL) peaks, which were assigned to quantum
defects formed by the chemical modification process. The intensity
of the red-shifted PL peak of SWNTs-xylyl significantly increased
after the separation. Compared to the sample before the separation,
the purified (6,5) SWNTs-xylyl exhibited a considerable red-shifted
PL with reduced concentration quenching effects. Owing to these properties,
the helicity sorting and optical resolution of functionalized SWNTs
may have practical applications as efficient NIR optical materials.