title: Understanding Charge Transport in Mixed Networks of Semiconducting Carbon Nanotubes.
abstract: The ability to select and enrich semiconducting single-walled carbon nanotubes (SWNT) with high purity has led to a fast rise of solution-processed nanotube network field-effect transistors (FETs) with high carrier mobilities and on/off current ratios. However, it remains an open question whether it is best to use a network of only one nanotube species (monochiral) or whether a mix of purely semiconducting nanotubes but with different bandgaps is sufficient for high performance FETs. For a range of different polymer-sorted semiconducting SWNT networks, we demonstrate that a very small amount of narrow bandgap nanotubes within a dense network of large bandgap nanotubes can dominate the transport and thus severely limit on-currents and effective carrier mobility. Using gate-voltage-dependent electroluminescence, we spatially and spectrally reveal preferential charge transport that does not depend on nominal network density but on the energy level distribution within the network and carrier density. On the basis of these results, we outline rational guidelines for the use of mixed SWNT networks to obtain high performance FETs while reducing the cost for purification.
authors: Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg , D-91058 Erlangen, Germany.|Institute for Physical Chemistry, Universität Heidelberg , D-69120 Heidelberg, Germany.
authors: Marcel
authors: M
authors: Rother
authors: Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg , D-91058 Erlangen, Germany.|Institute for Physical Chemistry, Universität Heidelberg , D-69120 Heidelberg, Germany.
authors: Stefan P
authors: SP
authors: Schießl
authors: Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg , D-91058 Erlangen, Germany.|Institute for Physical Chemistry, Universität Heidelberg , D-69120 Heidelberg, Germany.
authors: Yuriy
authors: Y
authors: Zakharko
authors: Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg , D-91058 Erlangen, Germany.|Institute for Physical Chemistry, Universität Heidelberg , D-69120 Heidelberg, Germany.
authors: Florentina
authors: F
authors: Gannott
authors: Institute for Physical Chemistry, Universität Heidelberg , D-69120 Heidelberg, Germany.
authors: Jana
authors: J
authors: Zaumseil
keywords: electroluminescence; network; photoluminescence; single-walled carbon nanotubes; transport