Aggregation-Induced Emission with Long-Lived Room-Temperature Phosphorescence from Methylene-Linked Organic Donor-Acceptor Structures.

Aggregation-caused quenching (ACQ), where excited-state and/or ground-state electronic structures are altered to exhibit an increased proclivity for non-radiative decay for the aggregates, is largely responsible for the lack of fluorescence and phosphorescence in molecular solids in general. Here we show that ACQ could be effectively circumvented by constructing an aromatic system with a methylene-linker, where the system exhibits typical aggregation-induced emission (AIE) with long-lived room-temperature phosphorescence, since the tetrahedral structure in the solid state may significantly reduce strong intermolecular interactions contributing to ACQ.