Engineering and optical characterization of large area, aligned single-wall carbon nanotubes

Single-wall carbon nanotubes (SWCNTs) possess unique optical and electronic properties due to their strictly one-dimensional nature and large aspect ratio, that can be enhanced at the macroscopic scale when the SWCNTs are well-aligned. Specifically, the low thermal interface resistance, highly polarized absorption and photoluminescence, and mechanical and transport properties show vast enhancement when the tubes are aligned. Engineering of a large-scale (mm²) architecture of aligned SWCNTs has challenged the community for years and presents a major drawback in their use in many applications. In addition, the reproduction of reported results in the CNT field remains a challenge due to insufficient methodical details and a lack of understanding of the role of certain experimental parameters. Recently, the first demonstration of high-quality aligned films of SWCNTs with 1.4 nm tube diameter was reported by X. He et al. The goal of our work is to refine and optimize their reported method and establish the robust capability to produce aligned macroscopic films at NIST using tubes of varying chiralities and surfactants. Creating monodomain, aligned films utilizes the technique of slow vacuum filtration, yet is complex due to tube sensitivities to electrostatics as well as other currently unquantified variables. Optimization of the method and development of a rigid protocol involves varying several parameters, including SWCNT concentration, surfactant concentration, and filtration flow rate. Once multiple films are produced, they need to be transferred from the polycarbonate nanopore membrane used during filtration onto other substrates for device fabrication and characterization, including polarized optical microscopy, Raman spectroscopy, and absorption. The status of the project will be presented and discussed.