Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 29: Graphene I
O 29.6: Talk
Tuesday, March 15, 2011, 12:30–12:45, WIL B321
Electrical conductivity of single functionalized graphene sheets measured by Kelvin probe force microscopy — Liang Yan1, •Christian Punckt2, Ilhan A. Aksay2, Wolfgang Mertin1, and Gerd Bacher1 — 1Werkstoffe der Elektrotechnik und CeNIDE, Universität Duisburg-Essen, Germany — 2Dept. of Chem. and Biolog. Engineering, Princeton University, USA
Functionalized graphene can be produced in bulk amounts by the thermal exfoliation of graphite oxide resulting in a material exhibiting a large fraction of single functionalized graphene sheets (FGSs) which – in contrast to pristine (e.g. ”Scotch Tape”) graphene – contain a large amount of functional groups and lattice defects. The number density of functional groups and defects can be tuned either by modifying the exfoliation process or by subsequent thermal reduction or annealing. FGSs have been used in various applications ranging from polymer nanocomposites to supercapacitors and batteries. In these applications, both the intrinsic resistance of the FGSs as well as the electrical contact between adjacent sheets limit device performance. By measuring the conductivity of individual FGSs employing Kelvin probe force microscopy, we can eliminate the contribution of contact resistance, analyze the intrinsic sheet conductivity with spatial resolution, and correlate electronic and topographical features. Despite their large degree of lattice disorder and functionalization, we obtain conductivities on the order of 105 S/m for individual sheets. Results are put in perspective with emerging applications and competing materials.