Effects of fluorine atoms and ionic structures on the liquid-crystalline properties of tetrafluorinated tolane-based luminescent ionic liquid crystals

Abstract

Imparting fluorescent properties to liquid-crystalline (LC) materials is one of the most promising approaches to creating fluidic fluorescent materials that can be applied to flexible devices. Our recent studies revealed that difluorinated tolane derivatives with an imidazolium bis(trifluoromethane)sulphonate-terminated decyleneoxy chain exhibited a SmA phase at around room temperature and a blue fluorescence in the SmA phase. In this study, tetrafluorinated tolane-based photoluminescent LCs were synthesized and their LC and PL properties were investigated to obtain stronger fluorescence under the LC phase. As a result, an increase in fluoro-substituents significantly weakened the fluorescence, but destabilized the crystalline phase to easily form the LC phase.