Exploring Size-Controlled Exciton Evolution Using DNA Libraries

To investigate multichromophore phenomena, progress traditionally relies on model covalent dimers for spectroscopic interrogation. Integrating molecular semiconductors into nucleic acid libraries can enable rapid screening of multichromophore phenomena. Here, we report DNA-directed assembly of up to five π-conjugated chromophores that demonstrate charge separation and electronic delocalization phenomena. We integrate a range of porphyrins and perylene diimides (PDIs)─molecular semiconducting materials widely used in organic electronic devices─in DNA, encoding nearest-neighbor assembly through base-sequence programmed hybridization. In this way, we can assemble multicomponent stacks with tailored electronic properties from a central chromophore-DNA library. This allows dimer and multimer production on demand, within hours, from presynthesized DNA-chromophores for spectroscopic analysis. We demonstrate the library's ability to optimize for charge transfer, computationally prescreening for close π-stacking as a proxy for large orbital overlap and exchange energy. Our modular DNA assembly reveals opportunities for rapid development of simple, bespoke chromophore architectures with stoichiometric chromophore control and ordering.