Penn State MRSEC: Center for Molecular Nanofabrication and Devices Mallouk T.E. DMR-0213623 Building and Moving a Nanoc

1. Penn State MRSEC: Center for Molecular Nanofabrication and DevicesMallouk T.E. DMR-0213623Building and Moving a Nanocar A long term goal of our work is to create electrical, optical, or mechanical sensors or actuators for organizing materials at nanoscale dimensions. To this end, we have designed, synthesized, and imaged a nanoscale molecular motor or “nanocar”, consisting of two sets fullerene “wheels” attached to hydrocarbon “axles” that are connected to a chassis. In the current arrangement, the chassis is off-axis from the axles, which enables clear identification of the nanocar’s orientation. These nanocars can be deposited on graphite surfaces and imaged by scanning tunneling microscopy. When the samples are heated, the cars move over the surface driven by thermal energy. More importantly when tip-sample distances are reduced, the cars can be pushed parallel to their chassis by the probe tip, demonstrating we have rudimentary control over these motors. We are currently investigating whether the fullerenes are rolling or sliding across the surface, and we are functionalizing the chassis with charged groups to enable manipulation by external electric fields. Figure 2: Moving a “nanocar”. By bringing the probe close to the surface, the molecule can be pushed parallel to the chassis, paving the way towards electric field-driven propulsion. Figure 1: Synthesizing and imaging a “nanocar”. The wheels and axle define the preferred direction of motion. Because of the asymmetric structure, the orientation of the molecule, which measures 3.3nm by 2.0nm, can be easily identified by scanning tunneling microscopy. Kevin Kelly (Rice), James Tour (Rice), Paul Weiss (Penn State)