Intermolecular Charge-Transfer Interactions Facilitate Two-Photon Absorption in Styrylpyridine-Tetracyanobenzene Cocrystals.

Cocrystals of 4-styrylpyridine and 1,2,4,5-tetracyanobenzene were successfully prepared by supramolecular self-assembly. Donor-acceptor interactions between the molecular components are the main driving force for self-assembly and contribute to intermolecular charge transfer. The cocrystals possess two-photon absorption properties that are not observed in the individual components; suggesting that two-photon absorption originates from intermolecular charge-transfer interactions in the donor-acceptor system. The origin of two-photon absorption in multichromophore systems remains under-researched; thus, the system offers a rare demonstration of two-photon absorption by cocrystallization. Cocrystal engineering may facilitate further design and development of novel materials for nonlinear optical and optoelectronic applications.