Aligned Carbon Nanotube Thin Films from Liquid Crystal Polyelectrolyte Inks

Daniel Tune, Adam Blanch, Cameron Shearer, Katherine Moore, Moritz Pfohl, Joseph Shapter, Benjamin Flavel

    Research output: Contribution to journalArticlepeer-review

    26 Citations (Scopus)

    Abstract

    Single walled carbon nanotube thin films are fabricated by solution shearing from high concentration sodium nanotubide polyelectrolyte inks. The solutions are produced by simple stirring of the nanotubes with elemental sodium in dimethylacetamide, and the nanotubes are thus not subject to any sonication-induced damage. At such elevated concentrations ( mg mL-1), the solutions exist in the liquid crystal phase and during deposition this order is transferred to the films, which are well aligned in the direction of shear with a 2D nematic order parameter of 0.7 determined by polarized absorption measurements. Compared to similarly formed films made from superacids, the polyelectrolyte films contain smaller bundles and a much narrower distribution of bundle diameters. After p-doping with an organic oxidizer, the films exhibit a very high DC electrical to optical conductivity ratio of μDCOP 35, corresponding to a calculated DC conductivity of over 7000 S cm-1. When very thin (T550 96%), smooth (RMS roughness, Rq 2.2 nm), and highly aligned films made via this new route are used as the front electrodes of carbon nanotube-silicon solar cells, the power conversion efficiency is almost an order of magnitude greater than that obtained when using the much rougher (Rq 20-30 nm) and less conductive (peak μDCOP 2.5) films formed by common vacuum filtration of the same starting material, and having the same transmittance.

    Original languageEnglish
    Pages (from-to)25857-25864
    Number of pages8
    JournalACS Applied Materials & Interfaces
    Volume7
    Issue number46
    DOIs
    Publication statusPublished - 25 Nov 2015

    Keywords

    • alignment
    • nematic
    • sodium nanotubide
    • solar cells
    • thin films

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