Role of ZnO Nanorods in Modulating the Dielectric Characteristics of Nematic Liquid Crystals for Dual-Frequency Applications

We report a systematic study on the effect of incorporating zinc oxide (ZnO) nanorods into the nematic liquid crystal 4-n-pentyl-4′-cyanobiphenyl (5CB), a room-temperature nematic with positive dielectric anisotropy and a dominant longitudinal dipole moment. Owing to their anisotropic geometry, ZnO nanorods couple effectively with the nematic director and modify the dielectric relaxation dynamics of the host matrix. A pronounced reduction of the relaxation frequency (fR) and crossover frequency (fc) is observed, with maximum reductions of 55 and ∼71%, respectively, at an optimal nanorod concentration of 0.05 wt %. The nonmonotonic concentration dependence highlights the critical role of nanorod-induced elastic and dielectric coupling in governing dual-frequency-like behavior. These results provide new insights into the role of anisotropic nanorods in simultaneously tuning fR and fc and establish ZnO–5CB nanocomposites as promising candidates for low-power, high-performance, dual-frequency nematic liquid-crystal devices.