Interaction between fluorene-based polymers and carbon nanotubes/carbon nanotube field-effect transistors

We study the interaction between fluorene-based conjugating polymers and various chiralities of single-walled carbon nanotubes (SWNTs). The fluorene-based polymers are able to selectively wrap the SWNTs with certain chiral angles or diameters (1.02~1.06 nm) depending on their chemical structures. This can be used to selectively extract or enrich certain species of nanotubes. For example, high purity of (7, 5) SWNTs (~79% of the semiconducting ensemble) can be obtained by fluorine-polymer assisted extraction from the narrow-diameter distributed SWNTs produced by the catalyst Co-MCM-41. In addition, we also study the interaction between fluorene-based polymers and SWNT networked field-effect transistors (SNFETs) by location-selective photo-excitation, where we find that the photocurrent generated in SNFETs is controlled by the energy-level alignment at the polymer-electrode interface and the SWNT-polymer interface is suggested to contribute to the dissociation of photo-generated excitons.