I am interested in understanding and harnessing photo-initiated charge and energy
transfer in nanoscale systems, with a focus on nanoscale assemblies such as
nanocrystal – organic molecule conjugates and peptide assemblies. This research has
broad implications for technologies as diverse as artificial photosynthesis, bio-imaging,
and quantum computation.
My current interests can be broadly divided into three categories: photoexcited charge
transfer from quantum dots, charge and energy transfer in peptides, and
photogenerated spin qubits in nanoscale systems. For background information and
explanations of some of the jargon, please visit the Olshansky Lab Website (link).
Photoexcited charge transfer from quantum dots
I seek to expand fundamental mechanistic understanding of photoexcited charge
transfer processes in quantum dots. I am especially interested in experimental model
systems composed of quantum dots covalently linked to molecular charge acceptors.
One way to glean mechanistic information from charge transfer processes is to alter the
free energies of either the charge donor or acceptor and see how this affects charge
transfer rates. In our quantum dot – molecular systems, we can tune the energy of the
donor (quantum dot) by changing the size, composition, or surface passivation, and we
can tune the energy of the acceptor (molecule) with synthetic attachment of electron
donating and withdrawing functional groups. I also aim to explore the effect of solvent,
temperature, physical distance, and a variety of other parameters in understanding
I plan to apply to results of this work to designing QD-molecular systems that can be
used in biologically relevant contexts such as dynamic fluorescent sensors.
Furthermore, I hope to extend my work to artificial photosynthesis applications by
designing systems that can perform photocatalytic and photoelectrochemical carbon
Charge and energy transfer in peptides
I am interested in using peptide and peptoid structures as scaffolds for exploring
questions of how photogenerated charges and energy propagate on the nanoscale. The
peptide structures will be both biologically inspired and artificial and will be designed to
support photoactive and redox active molecular moeities. Importantly, the automated
nature of peptide synthesis will allow these structures to be highly tailorable by simply
altering the sequence of residues. I hope to incorporate computational methods to
simulate the charge and energy propagation in these systems to learn something about
biological charge and energy transfer, and possibly apply this knowledge to creating
artificial light-harvesting systems.
Photogenerated spin qubits in nanoscale systems
In both systems described above, photoexcitation of an electron is followed closely in
time by charge separation. The resultant charge-separated state will consist of a radical
cation and a radical anion until the charges recombine or cause a chemical reaction.
However, while the charge-separated state exists, it possesses unique properties.
Specifically, the two unpaired electron spins associated with the two radicals (anion and
cation) will be correlated and in a well-defined quantum state. These photogenerated
charge states have been termed spin-correlated radical pairs or spin qubit pairs since
they have the potential to find applications in quantum information applications. I hope
to use electron paramagnetic resonance techniques to detect these spin qubit pairs in
the nanoscale systems described above.