Functionalized quantum dots and conjugated polymers for<br/><br/>light harvesting applications: Theoretical insights

Saturday, November 1, 2008 - 3:30pm - 4:00pm
EE/CS 3-180
Sergei Tretiak (Los Alamos National Laboratory)
Using density functional theory (DFT) and time-dependent DFT
quantum-chemical methodologies, we investigate interplay of electronic
properties and conformational dynamics in several optically active
materials. In quantum dots we explore the role of surface ligands on the
electronic structure and observe strong surface-ligand interactions leading
to formation of hybridized states and polarization effects. This opens new
relaxation channels for high energy photoexcitations. Computations of
Ru(II)-bipyridine attached to the semiconductor quantum dot systems
demonstrate possibility of charge separation and energy transfer processes
in the complex. In the amorphous clusters of conjugated polymers, we find
that electron trap states are induced primarily by intra-molecular
configuration disorder, while the hole trap states are generated primarily
from inter-molecular electronic interactions. All these phenomena govern
experimentally observed photoinduced dynamics and define technologically
important properties of materials suitable for solar energy conversion.
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