Selective Extraction of Large-Diameter Single-Wall Carbon Nanotubes with Specific Chiral Indices by Poly(9,9-dioctylfluorene-alt-benzothiadiazole)

Semiconducting single-wall carbon nanotubes (SWCNTs) having large diameters (d(t) > 1.3 nm) are successfully extracted in toluene by fluorene-based polymers. In particular, poly(9,9-dioctylfluorene-alt-benzothiadiazole) shows excellent selectivity for (15,4) SWCNTs. Although the importance of structural matching between the fluorene backbone and the tube surface has already been discussed, the present photoluminescence studies reveal that matching the energy levels between fluorene-based polymers and SWCNTs is crucial for selective nanotube extractions.