Key factor in enhancing yield and stability in single-chirality carbon nanotubes extraction: solvent viscosity

High-purity, monochiral single-walled carbon nanotubes (SWCNTs) are essential for advancing high-performance nano-optoelectronic devices. Nonetheless, conventional methods for chirality separation of SWCNTs face challenges, including low yield, poor solution stability, and inefficient film formation processes. This study revealed that the yield of monochiral (6,5) SWCNTs can be significantly enhanced by increasing solution viscosity within a low-polar solvent. Employing tetralin, a low-polarity and high-viscosity solvent, the concentration of the dispersion was enhanced by a factor of 19 relative to that in toluene, attaining the highest reported extraction yield of (6,5) SWCNTs with PFO-BPy. Additionally, a mixed-solvent strategy combining toluene and tetralin has been employed to achieve a balance between concentration and purity for (6,5) SWCNTs. Furthermore, the use of a high-viscosity solvent bolstered the stability duration of chiral SWCNT dispersions, as well as the deposition rate of SWCNT films, leading to superior chiral (6,5) SWCNT films. Field-effect transistors (FETs) fabricated using these films exhibited excellent performance, highlighting their substantial potential for use in high-performance electronic devices.