Photoexcited conductance measurements of novel porphyrin-chromophore molecular assemblies

COLL 51

Sanjini U. Nanayakkara1, Laura Kraya1, Tae-Hong Park2, Michael J. Therien2, and Dawn A. Bonnell, bonnell@lrsm.upenn.edu1. (1) Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA 19104, (2) Department of Chemistry, University of Pennsylvania, 231 S. 34th Street, Philadelphia, 19104-6323
We have measured photoexcited charge transport in individual porphyrin-chromophore molecules. Light illumination coupled to an ultra-high vacuum scanning tunneling microscope has enabled these measurements with single molecule resolution. This class of fully conjugated molecules includes a mono- or multi-chromophoric center, and a linker-group that terminates with a thiol functionality. The thiol functionality facilitates attachment to an Au substrate. Therefore, in order to isolate invidual and small groups of molecules we have utilized self- and directed-assembly techniques using alkanethiolate self-assembled monolayers (SAMs) on Au(111). The alkanethiolate SAMs provide a support matrix confining the porphyrin-chromophore molecules into precise assemblies for charge transport measurements. We recorded tunneling spectroscopy during light illumination and aim to understand the photoexcited conductance pathways of single molecules as a function of chemical structure.
 

Interfacial Electron Transfer and Solar Energy Conversion: From Molecules to Nanomaterials
2:00 PM-5:40 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 226, Oral

Division of Colloid & Surface Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008