Single-walled carbon nanotube growth using [Fe3(µ3-O)(µ-O2CR)6(L)3]n+ complexes as catalyst precursors

Abstract

We present herein the VLS growth of SWNTs from oxo-hexacarboxylate–triron precursors, [Fe₃O(O₂CCH₃)₆(EtOH)₃] (1) and [Fe₃O(O₂CCH₂OMe)₆(H₂O)₃][FeCl₄] (2), on spin-on-glass surfaces, using C₂H₄/H₂ (750 °C) and CH₄/H₂ (800 and 900 °C) growth conditions. The SWNTs have been characterized by AFM, SEM and Raman spectroscopy. The characteristics of the SWNTs are found to be independent of the identity of the precursor complex or the solvent from which it is spin-coated. The as grown SWNTs show a low level of side-wall defects and have an average diameter of 1.2–1.4 nm with a narrow distribution of diameters. At 750 and 800 °C the SWNTs are grown with a range of lengths (300 nm–9 µm), but at 900 °C only the longer SWNTs are observed (6–8 µm). The yield of SWNTs per unit area of catalyst nanoparticle decreases with the growth temperature. We have demonstrated that spin coating of molecular precursors allows for the formation of catalyst nanoparticles suitable for growth of SWNTs with a high degree of uniformity in the diameter, without the formation of preformed clusters of a set diameter.