Organic compounds with aggregation-induced emission

Light emissions of the organic dyes are often quenched when the luminophors are fabricated into solid thin films, which have greatly limited their scope of practical applications, such as organic light-emitting diodes, chemosensors/biosensors etc. So that, the organic compounds with excellent emission properties at aggregate state or solid state, that are, aggregation-induced emission (AIE), aggregation-induced emission enhancement (AIEE) and crystallization-induced emission enhancement (CIEE) properties, attract more and more attentions. They can get tunable intensity and wavelength of emission by adjusting molecular structure, twisted conformation, rigidity of structure and stack morphology etc. This review focuses on the structures and mechanisms about AIE, AIEE and CIEE. The kinds of compounds with AIE, AIEE and CIEE are summarized, mainly including siloles, substituted ethenes (including fulvene and DPDSB style), CN-substituted phenylene vinylenes, pyrans, biphenyl compounds and polymers. Herein some theories explaining AIE, AIEE and CIEE are introduced including RIR (restriction of intramolecular rotation), non-activation by avoiding non-radiative decay, preventability of excimers by twisted conformation, J-aggregate state and intermolecular C-H/π interaction.