Deoxyribonucleic Acid Encoded and Size-Defined π-Stacking of Perylene Diimides

Area of Science:

• Organic electronics
• Supramolecular chemistry
• DNA nanotechnology

Background:

• Natural photosystems utilize protein scaffolds for efficient exciton and charge transfer.
• Current organic electronic devices lack precise structural control over molecular interactions.
• Developing methods for controlled assembly of organic semiconductors is crucial for device performance.

Purpose of the Study:

• To report DNA-encoded assembly of perylene diimides (PDIs) with deterministic control over molecular arrangement.
• To establish a versatile "toolbox" for constructing custom semiconductor stacking sequences.
• To investigate the impact of controlled assembly on excited state evolution and charge dynamics.

Main Methods:

• Integration of PDIs into DNA chains using phosphoramidite coupling chemistry.
• Utilizing DNA sequence selection and intermolecular hybridization for precise positioning.
• Employing a hierarchy of interactions including DNA guidance, hydrophobic-hydrophilic effects, and electrostatic interactions for controlled aggregation.

Main Results:

• Achieved deterministic control over the number and stacking sequence of electronically coupled PDIs.
• Observed substantial intermolecular π-orbital overlap in assembled PDIs.
• Demonstrated evolution of singlet excited states from localized excitons to delocalized excimers in PDIs.
• Identified a shift in the dominant triplet formation mechanism with increasing PDI delocalization.

Conclusions:

• Modular DNA-based assembly provides molecule-by-molecule precision for bespoke semiconductor architectures.
• This approach offers significant opportunities for rapid development of advanced organic electronic materials.
• Controlled intermolecular interactions are key to tuning excited-state properties and charge transport in organic semiconductors.