Colloidal Crystals Engineered with DNA and Perylenediimide Exhibit Symmetry-Breaking Charge Transfer

Abstract

Perylenediimide (PDI) and its derivatives are widely studied for their photophysical and photochemical properties, making them promising candidates for photonic materials, organic semiconductors, and molecular qubits. However, the lack of control over their aggregation pathways and charge-transfer coupling severely limits their uses. Here, we report the synthesis of PDI-DNA bioconjugates as a new class of “programmable atom equivalents” (PAEs), in which a single PDI core is covalently linked to two DNA strands. Unlike conventional PAE superlattices formed by slow thermal annealing, the vapor-diffusion crystallization method enables the colloidal crystallization of PDI–DNA conjugates into large single-crystalline superlattices through cooperative DNA hybridization and PDI π–π stacking. The peripheral four sticky ends hybridize into a DNA framework, which serves as a scaffold, organizing the PDI cores into well-defined dimers, rather than disordered aggregates or micelles. The dimeric building units are rigid yet highly dynamic due to the intrinsic flexibility of the linkers, yielding superlattices with programmable PDI packing geometries and adaptiveness upon structural modifications. For most PDI crystals, PDI units stack continuously in one dimension to maximize interactions, which tend to hinder charge separation. Here, DNA not only encodes sequence-specific interactions but also sterically and electrostatically isolates PDI dimers as discrete photonic units into solid-state optically active materials. The structural tunability of the system can be readily adjusted by varying the PDI core or the linker length between the PDI core and the DNA shell. Notably, these superlattices exhibit photoinduced symmetry-breaking charge transfer distinct from that of monomers or micellar aggregates.