Molecular Crystals and Liquid Crystals, Vol.428, 17-32, 2005
Colorless molecular dopants for low-operating-voltage nematic liquid crystals
In this paper we present a study of two similar, colorless molecular dopants designed to decrease the operating voltages of nematic liquid crystals by increasing the dielectric anisotropy. Experimental analysis shows that these materials reduced the threshold voltage (voltage associated with the Freedericksz transition) by up to 20%, but via a reduction in the liquid crystal order parameter. To gain insight into the decrease of the order parameter, we used density-functional and single-point MP2 theory to investigate the conformational preferences of our dopants; the calculations suggest that, because of steric interactions, the conformations adopted are rather rigid.