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Jay Dicke, Website Profile Update.
In recent years, the use of single molecules, especially organic molecules, as the
principal components in electronic devices has received a great deal of attention. A host
of single molecule devices including switches, rectifiers, and transistors, among others,
have been fabricated since a single-molecule rectifier was first proposed in 1974. The
continued improvement of molecular electronic device performance requires a
fundamental understanding of electron transfer processes in organic molecules.
Typically, we use Donor-Bridge-Acceptor (DBA) systems as model complexes to study
the effect of different bridge structures on the charge transfer mechanism.
Figure 1: Schematic representation of a DBA system.
The quantum nature of single molecules will significantly impact the electron
transport properties of a device. For example, the transport of electrons between two
metal contacts with either a cross-conjugated molecule or a meta-connected benzene
ring, both of which act as a potential barrier for coherent electron transfer, has received a
large amount of attention theoretically and some experimental attention. In these devices,
large anti-resonances attributed to these classes of connecting molecules are found to
impede transmission of an electron as the potential bias is scanned. Theoretical work has
shown that these anti-resonances are due to destructive interference of multiple molecular
pathways. I have synthesized DBA’s utilizing para- and meta-connected
oligophenyleneethynylenes to study these effects.
Figure 2: Structure of some DBA’s synthesized to study the effect of the crossconjugated bridge.
We utilize several techniques including femtosecond transient absorption (fsTA),
nanosecond transient absorption (nsTA) and transient CW and pulsed EPR to study the
kinetics and electronic properties of these systems.