DNA-templated programmable excitonic wires for micron-scale exciton transport

Abstract

<h2>Summary</h2> Rationally designed photonic complexes promoting the efficient collection and harnessing of excitation energy are key to artificial photosynthesis and optoelectronics. The precise control over the geometric arrangement and energy flow of photonic materials is in great demand. Mimicking natural light-harvesting systems in terms of multi-pigment complexes well organized by protein scaffolds, herein, we report programmable photonic materials directed by structural DNA templates. Four-helix-bundle DNA origami was used to guide the assembly of the cyanine dye K21 to form closely packed dye aggregates exhibiting strong excitonic coupling between chromophores. This enables sub-micron-scale exciton migration, demonstrated by spectroscopic measurements and theoretical modeling. The DNA-templated dye aggregates acting as "excitonic wires" could mediate directional energy transfer over a half-micrometer distance and were further programmed to achieve geometric complexity and modular bottom-up fabrication of higher order photonic architectures. This work offers a rich toolbox to design and create complex photonic devices and excitonic networks.