Electronic structure in conjugated
molecular monolayers: charge transport levels and Fermi level
alignment
STEVEN W.
ROBEY
Department of
Commercce
National Institute of
Standards & Technology
Successful utilization of
conjugated molecular systems in electronic applications, either in the
guise of thin films for organic light emitting diodes (OLED's) or
field effect transistors or more speculative applications proposed for
molecular electronics, requires understanding of the molecular
electronic structure, including modifications occurring due to
coupling to electrodes. We have investigated the electronic
structure and coupling for a series of self-assembled monolayers
on gold , based on the prototypical "molecular wire",
4,4¢-(ethynylphenyl)-1-benzenethiol (C6H5-C_C-C6H4-C_C- C6H5-SH)
(OPE), employing a combination of one- and two-photon photoelectron
spectroscopies. This combination allows access to information on
both occupied and unoccupied levels. Details of the electronic
structure for OPE will be discussed along with the influence of
substitutions on the central ring, perturbations due to the thiol-Au
coupling, and the shift in Fermi level alignment due to changing the
linking group from thiol to -NC.