Highly fluorinated biphenyl ether systems as dopants for fast-response liquid crystal display applications

Abstract

The overall display performance of representative commercially available +LC and –LC liquid crystal (LC) mixtures may be improved by the addition of small quantities of penta-, tetra- and tri-fluorinated biphenyl ether dopant systems. Synthetic routes for the preparation of the fluorinated dopants by nucleophilic aromatic substitution processes are described, and a range of electro-optical measurements of the doped LC mixtures, including LC rise and decay times, rotational viscosity, dielectric anisotropy, phase transition temperature and voltage holding ratios, were obtained. In general, the performance of the LC systems were improved by fluorobiphenyl ether doping, as determined by response time and rotational viscosity measurements, and figure of merit (FoM) calculations.