Control over the temporal and spatial evolution of molecular excited states is critical to developing excitonic systems for light-harvesting, computing, and imaging. While natural light-harvesting systems achieve the required control through precise chromophore placement, this has been challenging to replicate in synthetic systems. Here we use DNA-chromophore assemblies to generate delocalized excitonic circuits with nanometer-scale precision over chromophore placement and orientation. Using multidimensional and single-molecule spectroscopy, we show how chromophore placement within a tunable DNA scaffold can be used to control electronic coupling and system-bath coupling independently. With this platform, we explore the role of these parameters in mediating exciton transport. We then expand this framework to demonstrate how distortions in the DNA scaffold can be leveraged to tune photophysical properties of the resultant delocalized exciton. Using single-molecule spectroscopy, we demonstrate how these properties can be used in fluorescence lifetime imaging. Collectively, control over excitons and their dynamics with DNA nanostructures, as presented here, offers design principles for molecular electronics and nanophotonic devices.

Controlling exciton dynamics with DNA nanostructures

ACS Spring Meeting 2021

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