Combined experimental and theoretical study of one- and two-photon absorption properties of D-π-A-π-D type bis(carbazolylfluorenylethynyl) arene derivatives: Influence of aromatic acceptor bridge

摘要

This article reports the design and synthesis of five new donor-π-acceptor-π-donor derivatives where carbazolylfluorenyl serves as donor; arenes serve as central core acceptors, and acetylene group as a π bridge. Comprehensive one- and two-photon absorption properties of these compounds were studied experimentally and theoretically. The two-photon absorption cross-sections were measured by using two-photon excited fluorescence spectrometer and showed significant enhancement from 560 to 2600 GM. In general, the two-photon absorption cross-section values increase with respect to the strength of the acceptor bridge (arenes) in the order of benzene < thiophene < fluorene < anthracene < benzothiadiazole and with the increase of excited state transition dipole moments. The calculated two-photon absorption cross-section values and trends are in good agreement with the experimental results. The combination of large two-photon absorption cross-sections and high emission quantum yields makes the dyes attractive for applications involving two-photon excited fluorescence.