Frequency Modulation and Capacitance-Amplification of TN-LCD Embedded with Metal Nanoparticles of Pd and Ag Using Equivalent Circuit Analysis

A twisted nematic (TN) liquid crystal displays (LCDs) with embedded Pd and Ag nanoparticles covered with a diffusion cloud exhibits peculiar frequency-dependent behavior. In particular, no TN response is observed below the frequency, f2 (2 Hz) that is far below the dielectric relaxation frequency, fR, whereas above this frequency, revival of the TN response occurs, where LC of 5CB was used. This device is called frequency modulation (FM) TN-LCD and its behavior is attributed to the reduction of the dielectric anisotropy
far below the relaxation frequency, fR. However, above this frequency, the revival of the torque driving the TN-CD occurs, and the operation of the TN-LCD is revived with a quick response speed. The reduction of
may be due to the prevailing of the amplified dielectric constant caused by the inclusions covering the entire region. However, above fR, this amplification gradually vanishes and the normal TN-operation is revived due to the revival of the dielectric torque force. In this paper, an interpretation of the FM-LCD operation through dielectric spectroscopy and equivalent circuit analysis is presented. Interpretation of the dielectric constant amplification, whose factor, Ac, is equal to10 and 52 with the NPs of Pd and Ag, respectively, through a postulation of negative
2 for the inclusions (NPs and diffusion cloud) is also presented.