Dielectric properties of frequency modulation twisted nematic LCDs doped with palladium (Pd) nanoparticles

Twisted nematic liquid crystal display (TN-LCD) devices, composed of nematic liquid crystal (NI-Q, doped with palladium (Pd) nanoparticles, which are protected with the same NLC molecules of 5CB (Merck, K-15), show electrooptic characteristics that are featured by a frequency modulation and fast response. This device is called FM-TN-LCD. In this paper, we report that the frequency range in the FM-TN-LCD spreading from tens Hz to an upper limit 1 kHz, depending on the concentration of nanoparticles, con-elates with that of the dielectric dispersion of the sample cell, which is expressed analytically by the Maxwell-Wagner theory on the heterogeneous dielectric medium, where the dielectric relaxation frequency, and thus the dielectric relaxation time, are primarily governed by the electrical conductivity of the doped nanoparticles of Pd and their concentrations.