Zhengquan Yan

Advances in synthesis and application of near-infrared absorbing squaraine dyes

Due to the specially rigid, planar and zwitterionic structures, squaraine dyes have strong absorption (e ≥ 105 L mol−1 cm−1) in the visible to near-infrared region. Therefore, squaraine dyes have been extensively investigated from both fundamental and technological viewpoints. To present the readers a better understanding of the important dyes, in this article, we will highlight the recent synthetic developments of squaraine derivatives as a class of functional near infrared absorbing optic materials and their application in the areas of anti-aggregation, sensor, solar cell, nonlinear optics and self-assembly functional materials based on our own work during the recent years.

Supramolecular self-assembly structures and properties of zwitterionic squaraine molecules

To further investigate the influence of H-bond combining with π–π stack interaction on the optical performances, a few rigid zwitterionic squaraine molecules, with different terminal H-bond recognition abilities, are identified and designed. They can controllably construct a series of supramolecular self-assemblies with different morphologies and dimensions via a simple solution-based self-assembly method under mild conditions. The morphologies, synergetic reinforcing effect, and optical-thermal properties are investigated and confirmed by both theoretical and experimental methods. The results indicate that the morphologies of the resultant self-assemblies can be effectively controlled by rational molecular design, whose absorption and emission spectra and thermal stabilities accordingly change with the alteration of zwitterionic squaraine molecular structures.

Preparation and properties of a functional polyacetylene with quinoline-based heterocyclic azo pendants

A novel functional polyacetylene with D-π-A conjugated quinoline-based heterocyclic azo pendants was designed and prepared to improve the polyacetylene properties. Its structure and properties were characterized and evaluated in details. The incorporation of D-π-A conjugated quinoline-based heterocyclic azo pendants to the polyacetylene backbone increases the polymer solubility in polar solvents. Its UV-vis absorbance is sensitive to the presence of F− anions and results in UV-VIS spectrum red-shift by ca. 21 nm from 449 nm to 470 nm in dry DMSO.