Impedance and quantitative TGA characterization of transparent carbon nanotube thin films

Many applications currently under development have given rise to a great interest in transparent conductive thin films of single‐walled carbon nanotubes (SWCNTs). In order to construct reproducible devices with similar properties, in particular with similar impedance Z(ω), it is important to associate the electrical properties with the amount of SWCNTs in a network. We obtained thin networks of SWCNTs on transparent flexible substrates (PPC, polypropylene carbonate) with different densities of carbon nanotubes. Using a mathematical approach, the amount of SWCNTs was determined by TGA. From optical absorption spectroscopy, we were also able to estimate the relative amount of SWCNTs. The two methods are in quite good agreement. We analysed the various samples using an Agilent Impedance analyser up to 110 MHz. When the density was increased, the electrical resistance decreased and the cutoff frequency was displaced to higher values. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)