The intense current interest in harnessing the unique electrical properties of molecules for devices has resulted in a number of recent attempts to position molecules in various configurations between electrodes. While direct positioning of individual molecules with microscopic probe tips is attractive for fundamental exploration, the method of solution self-assembly appears to be the most efficient way to make large numbers of devices with reproducible properties. The basic feature of self-assembly is that the system spontaneously forms itself. Thus, in order to achieve desired configurations of complex, electroactive molecules at electrode surfaces it is first necessary to learn the "rules" for the associated self-assembling processes. Using these, one can choose molecules, electrode surfaces and conditions to achieve the desired results. In this talk, results from our lab, in collaboration with other groups, will be presented that demonstrate some of the important aspects of solution self-assembly at gold and semiconductor electrodes. Of particular interest will be the control of the surface density of the electroactive molecules and their surface orientation. In addition to fully self-assembled devices, there also are hybrid fabrication devices in which deposited metal contacts are made to ensembles of pre-assembled molecules at surfaces. This talk also will discuss issues and current results relating to the high degree of chemical control required in making a metal atom-molecule contact.
David L. Allara
Professor of Chemistry and Professor of Materials Science, Pennsylvania State University
185 MRI Bldg., University Park, PA 16802 USA
Phone: (814) 865-2254; FAX: (814) 863-0618
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