One-step sorting of nearly single-chiral carbon nanotubes with (10,9) chirality of 1.3 nm diameter by backbone planarization of polydioctylfluorenes

Abstract

The conjugated polymer wrapping method has been developed to sort semiconducting single-walled carbon nanotubes (sc-SWNTs). However, the method has rarely been applied in sorting nearly single-chiral SWNTs with large diameter despite the necessity of separating sc-SWNT with homogeneous optoelectrical characteristics for high-performance devices. In this study, nearly single-chiral sc-SWNTs with a 1.3 nm diameter are sorted via only conjugated polymer wrapping method using poly (9,9-dioctylfluorenyl-2,7-diyl) (PFO) in tetralin, without additional process. The PFO backbone chain is extended with a torsion angle of 180° in tetralin owing to strong intermolecular forces from the viscous solvent. Consequently, the backbone planarization of PFO enables the sorting of SWNTs of specific chirality. The phase of the wrapping polymer results in an enhanced chiral selectivity, with over 70 % of the sorted SWNTs in tetralin having a chirality of (10,9). These findings clarify the relationship between the conformation and chiral selectivity of the wrapping polymer in the conjugated polymer wrapping method and contribute to the development of highly uniform SWNT-based devices, which require single-chiral SWNTs with homogeneous optoelectrical characteristics.