New cyano-substituted organic dyes containing different electrophilic groups: Aggregation-induced emission and large two-photon absorption cross section

Three aggregation-induced emission active dyes (3a-c) were synthesized and their one- and twophoton absorption properties have been investigated. They were all found to be weakly fluorescent in THF solution, while they exhibited dramatic fluorescence enhancement in water/THF mixtures. The solid fluorescence of 3a-c was recorded and their fluorescence quantum efficiency (φ_f) values were determined to be 8.0%, 8.1%, and 16.4%, respectively. Moreover, the two-photon absorption (2PA) crosssections (σ) of 3a-c were measured and 3a showed the highest value of 702 GM The excellent aggregation-induced emission and 2PA properties provide a promising alternative for biophotonic materials.