Optical properties of thiophene-containing liquid crystalline and hybrid liquid crystalline materials

We report new mesogens made of thiophene and stilbene moieties as main building blocks that exhibit nematic and/or smectic phases. The liquid crystalline properties of their thiophene/azobenzene analogues have been found to be strongly suppressed compared to their thiophene/stilbene analogues. In twinned “bent-core” thiophene/azobenzene compound relatively strong fluorescence was found. A new hybrid material built of AuNPs coated with a thiophene-containing mesogenic ligand that forms a smectic phase is shown. In solutions of thiophene-mesogen coated AuNPs an unusual decrease of the ligand fluorescence decay rate was observed. Fluorescence lifetime increase is ascribed to two-point anchoring of ligand molecules resulting in molecule orientation tangential to the AuNP surface. UV-Visible absorption and fluorescence data of all synthesised compounds are presented.