Propeller-like D–π–A architectures: bright solid emitters with AIEE activity and large two-photon absorption

Two novel molecules TABzPA and TATpPA with D–π–A structure and large π-conjugation have been synthesized via Wittig reaction. Unlike common molecules, which exhibit the aggregation-caused quenching (ACQ) phenomenon, TABzPA and TATpPA exhibit aggregation-induced emission enhancement (AIEE) activity: weak luminescence in common solvents but strong emission when aggregated as nanoparticles and solid powders. Due to their intramolecular charge transfer (ICT) attribution and AIEE features, TABzPA and TATpPA display bathochromic effects. Combining ICT and AIEE features, these molecules are intensely yellow solid emitters with high quantum efficiencies of about 23.2% and 24.1%. Moreover, TABzPA and TATpPA have excellent two-photon absorption (2PA) properties owing to good planarity and large π-conjugation. The values of 2PA cross sections at 800 nm are 7590 GM and 7648 GM. The excellent optical properties of TABzPA and TATpPA pave the way for future potential applications in biophotonics and optoelectronics.