Charge Transfer Dynamics in Supramolecular Tessellations Composed of Aromatic Donors and Chiral Tris(naphthalenediimide) Triangular Acceptors

Understanding charge transfer (CT) dynamics in donor-acceptor (D-A) cocrystals is important for the development of efficient organic photovoltaic and electronic materials. This study explores the photogenerated CT states of supramolecular tessellations formed by cocrystallizing a chiral tris(naphthalenediimide) triangular prism (-)-NDI-Δ with pyrene, perylene, and peri-xanthenoxanthene electron donors. By manipulating crystallization conditions, one-dimensional (1D) and two-dimensional (2D) cocrystals with distinct structural motifs and morphologies are achieved. Femtosecond and nanosecond transient absorption microscopies and time-resolved electron paramagnetic resonance spectroscopy were employed to elucidate the CT state dynamics. Our findings reveal that the CT state lifetimes are lengthened in the 2D cocrystals relative to the 1D cocrystals, which is attributable to the symmetry and molecular packing differences between them that modulate the CT interactions. This work highlights the potential of using preorganized covalent multisite charge carriers as donors or acceptors in cocrystals as a strategy for engineering structures for advanced multifunctional materials with tunable CT properties.