(Liq. Cryst.) A Room-Temperature Heptazine Core Discotic Liquid Crystal
writer：Mir Sayed, S.; Lin, B.; Deng, L.; Yang, H.*
keywords：Liquid Crystal
source：期刊
specific source：Liquid Crystals, 2017, 44, DOI: 10.1080/02678292.2017.1371343
Issue time：2017年
Heptazine is the fundamental structural and functional unit of graphitic carbon nitrides (g-CN) and has a π-conjugated planar symmetry with semiconducting properties. Molecular self-assembly is one of the key factors to drive the electronic behaviour of π-conjugated organic molecules. To enhance the semiconductivity, heptazine is decorated at its active sites with 2,3,5-tris(dodecyloxy)aniline to get well-organized columnar packing. A novel heptazine-core room-temperature discotic liquid crystal (HDLC) with hexagonal columnar geometry is discovered. The molecular structure and mesomorphic properties of HDLC are investigated by 1H-NMR, 13C-NMR, IR, POM, DSC and XRD. Photophysical and electrochemical properties of HDLC are studied by UV-Vis/fluorescence spectroscopy and cyclic voltammetry, respectively. The energy band gap of HDLC estimated from CV at room temperature is 1.63 eV, which is much narrower than the previously reported band gap for heptazine derivatives. This decrease in the energy band can be attributed to the particular designing of HDLC for columnar packing. As a columnar liquid crystal providing a smooth path to the charge transport, HDLC with such a narrow energy band gap may find applications in organic electronics.