Competition between Arene-Perfluoroarene and Charge-Transfer Interactions in Organic Light-Harvesting Systems

Two typical types of luminescent organic cocrystals comprising pyrene-octafluoronaphthalene (pyrene-OFN) and pyrene-1,2,4,5-tetracyanobezene (pyrene-TCNB) were developed by a simple supramolecular assembly strategy. The cocrystals exhibit distinct optical properties because of their different intermolecular interaction modes; that is, areneperfluoroarene (AP) and charge-transfer (CT) interactions. Unexpectedly, a pyrene-TCNB system with strong CT interactions was incorporated into a pyrene-OFN host as a robust guest to generate white-light emission (WLE). In the supramolecular cocrystal system, an efficient energy-transfer process from pyrene-OFN to pyrene-TCNB occurred because of the well-matched spectra of the constituents and a desirable energy donor/acceptor (D/A) distance. The present competitive intermolecular interaction strategy could be applied to the fabrication of more complicated organic light-harvesting systems.