Polymer-Sorted Semiconducting Carbon Nanotube Networks for High

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Polymer-Sorted Semiconducting Carbon Nanotube Networks for High-Performance Ambipolar Field-Effect Transistors Stefan P. Schießl,† Nils Fröhlich,‡ Martin Held,† Florentina Gannott,† Manuel Schweiger,† Michael Forster,‡ Ullrich Scherf,‡ and Jana Zaumseil*,†,§ †

Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen D-91058, Germany Chemistry Department and Institute for Polymertechnology, Bergische Universität Wuppertal, Wuppertal D-42119, Germany § Institute for Physical Chemistry, Universität Heidelberg, Heidelberg D-69120, Germany ‡

S Supporting Information *

ABSTRACT: Efficient selection of semiconducting single-walled carbon nanotubes (SWNTs) from as-grown nanotube samples is crucial for their application as printable and flexible semiconductors in field-effect transistors (FETs). In this study, we use atactic poly(9-dodecyl-9-methyl-fluorene) (a-PF-1-12), a polyfluorene derivative with asymmetric side-chains, for the selective dispersion of semiconducting SWNTs with large diameters (>1 nm) from plasma torch-grown SWNTs. Lowering the molecular weight of the dispersing polymer leads to a significant improvement of selectivity. Combining dense semiconducting SWNT networks deposited from an enriched SWNT dispersion with a polymer/metal-oxide hybrid dielectric enables transistors with balanced ambipolar, contact resistance-corrected mobilities of up to 50 cm2·V−1·s−1, low ohmic contact resistance, steep subthreshold swings (0.12−0.14 V/dec) and high on/off ratios (106) even for short channel lengths (