Spin-on catalyst: Straightforward and flexible route to substrate-grown single wall carbon nanotubes

The synthesis and characterization of single-wall carbon nanotubes (SWNTs) from simple catalytic precursors at 900 °C from methane and hydrogen is demonstrated. The catalyst precursor is comprised of iron nitrate and a commercially available siloxane polymer solution and is applied to various substrates via spin coating or dipping. The siloxane matrix simultaneously provides for the controlled formation of catalytic nanoparticles via phase separation and, upon heating, a smooth, continuous film of SiOx, which prevents catalyst coarsening and agglomeration at growth conditions. Furthermore, the processibility of the polymer enables the formation of complex, 3D structures from which nanotubes can grow. This combination of processing ease, flexibility, and inherent multifunctionality provides facile, controllable growth of single-wall carbon nanotubes on a multitude of substrates and facilitates additional routes toward SWNT-based device fabrication.