Sigma Xi Poster Session Submission

 

Post-doctoral Presenter:  Laura B. Picraux

Mentor:  Dr. Roger D. van Zee

Division 836, Chemistry, Room B161, Building 217, Mail Stop 8360, Telephone 301-975-3298, Fax 301-896-5924, laura.picraux@nist.gov, not a member of Sigma Xi.

Poster Category:  Chemistry

 

Title:  Valence electronic structure of oligo(phenylene vinylene)thiolate self-assembled monolayers on gold.

 

Authors:  Laura B. Picraux, Yamil Simon-Manso, Steven W. Robey, Roger D. van Zee, Christopher D. Zangmeister, Lawrence R. Sita, and Nadine E. Gruhn

 

Abstract:  Recent studies have shown that oligo(phenylene vinylene)thiolate (OPVs) self-assembled monolayers are more conductive than the well-characterized oligo(phenylene ethynylene)thiolate monolayers, implying that devices with improved performance may be created using OPVs.  This finding prompted a careful investigation of monolayers of OPVs in an effort to determine what factors are improving the transport properties.  Three OPV molecules were synthesized, and monolayers of these OPVs were prepared on vapor-deposited gold films.  The structural properties of these monolayers were characterized, and the electronic structure was investigated with ultraviolet photoemission spectroscopy.  The data show that these compounds form ordered, upright monolayers. The valence states of these monolayers can be understood by comparison to that of the well-studied para-(phenylene vinylene) polymer and charge-injection barriers estimated from this comparison. To further understand the factors that influence band line-up, new systems are being explored which change the substrate-molecule linking chemistries. With these new systems, we hope to better understand the orbital nature of the charge transport chemistry and be able to better predict how changing the structure of the molecule or the substrate will affect the observed transport properties.