A novel D-A-D-A-D type molecule based on substituted dihydroindolo [3, 2-b] carbazole with large two-photon absorption cross section and excellent aggregation-induced enhanced emission property

Two novel D-A-D-A-D type molecules T1 and T2 based on substituted dihydroindolo [3, 2-b] carbazole with large two-photon absorption (2PA) cross section and excellent aggregation-induced enhanced emission (AIEE) property have been synthesized and characterized. Both compounds emit weakly fluorescent in THF, while a significant AIEE property is observed in water/THF (v/v 50%/50%) for T1 and water/THF (v/v 90%/10%) for T2 with a sharp increase in fluorescence intensity. The solid fluorescence of T1 and T2 is located at 575 nm and 588 nm, and their quantum efficiencies are determined to be 3.2% and 5.8%, respectively. The corresponding 2PA cross section values for T1 and T2 at 800 nm are 867 GM and 1300 GM by the open-aperture Z-scan technique. These excellent performances of both compounds make them as attractive alternatives for biophotonic and optoelectronic applications.

Graphical abstractDownload full-size imageTwo novel D-A-D-A-D type molecules T1 and T2 based on substituted dihydroindolo [3, 2-b] carbazole have been synthesized and characterized. Both dyes exhibit excellent aggregation-induced emission enhancement (AIEE) property and the corresponding solid fluorescence is located at 575 nm and 588 nm. The value of the two-photon absorption cross section for T2 is 1300 GM at 800 nm by the open-aperture Z-scan technique.