| Nematic liquid crystal (NLC) is a kind of widely used optical material. In recent years, some researchers found that the property of nematic liquid crystals can be changed significantly by doping dopants. This paper will study the electro-optical properties of NLCs doped with silver nanoparticles.First, the threshold voltage and response time of the Electrically Controlled Birefringence (ECB) cells and Distortion Arrangement Perpendicular (DAP) cells were studied theoretically. The theoretical results show that the threshold voltage and response time of liquid crystals depend on dielectric anisotropy of liquid crystals. And doping silver nanoparticles can effectively increases the dielectric anisotropy of NLCs. Thus our theoretical results indicate that doping silver nanoparticles can decrease threshold voltage and response time of the ECB cells and DAP cells.Then we measured the threshold voltage and response time of ECB cells and DAP cells experimentally which were filled with positive NLC and negative NLC doped with silver nanoparticles. The experimental results show that by doping silver nanoparticles the threshold voltage and response time of both kinds of cells can be decreased, which is consistent with the theoretical results.The enhancement of electro-optical properties by doping nanoparticles under DC electric field is more significant than that under AC electric field. This can be explained by that doping silver nanoparticles can effectively enhance the dielectric anisotropy of NLC. The experimental result is consistent with the theoretical result. Besides, we find that doping sliver nanopaticles can decrease the concentration of the ion-charge. This effect is more considerable for DC electric field. Introducing sliver nanopaticles into the system can increase viscosity of NLCs. However, the contribution to the response properties of NLC from this factor can be neglected relative to those from the electric field and the elastic moment.
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