Synthesis, two-photon absorption and optical limiting properties of new linear and multi-branched bithiazole-based derivatives

In this work, a new series of linear and multi-branched bithiazole-based dyes (BTZ-I-IV) possessing terminal triphenylamine group were synthesized and characterized, and their one-and two-photon absorption properties have been investigated. These new compounds exhibited large two-photon absorption cross sections (σ), in which the σ data measured by the open aperture Z-scan technique were determined to be 173, 429, 1132 and 1665 GM for BTZ-I, BTZ-II, BTZ-III and BTZ-IV, respectively. A considerable increase in the value of 2PA cross section was obtained when triple bonds were introduced and the dimensionality and chromophore density increased.