Center for Functional Nanomaterials Seminar

Our research has focused on imaging, manipulation, and spectroscopy at the nanoscale including the investigation of single molecule electronic and mechanical devices. To understand the mechanics of nanoscale motion and manipulation in molecular systems, we have used scanning tunneling microscopy (STM) to probe a family of molecules based around the concept of the Nanocar. We observed these molecules at various temperatures and demonstrate the recognition of spinning vs. stationary fullerene wheels on the nanocar molecules by correlating the rotational state with observed changes in their electronic properties. Coupled with this, we have imaged the conformational changes of a fullerene dimer structure which included an azobenzene-based linkage. In addition to the above, we have employed STM to study polymer nanowires as candidates for molecular electronics. Analysis of polydiacetylene nanowires on different substrate electrode materials at varying sample bias voltage conditions reveals interesting substrate-dependent effects. The differing chemical and electronic interactions are quantified by dI/dZ and dI/dV spectroscopic images. We performed similar measurements on poly(3-hexylthiophene) nanowires. These studies open a new realm in the characterization and understanding of nanometer-sized mechanical, chemical, and electrical systems.