含奈米雜質之向列型液晶的光電特性

Abstract

向列型液晶是目前常被使用的液晶材料，尤其在市面上的LCD螢幕，大部分都是以向列型液晶做為材料。有研究指出在正型液晶中摻入奈米碳管(nano-tube)會改變原本液晶的光學反應，故我們使用在市面上最常被使用的MJ991597做為我們的材料，並且混合奈米鑽石碳粉、TiO2並從中發掘光學反應上是否有改變。我們使用cell gap為4μm，TN90度的液晶胞注入MJ991597的液晶材料，並分別摻入0. 1%，0.3%及0.5%的奈米鑽石碳粉及TiO2來量測外加電壓對穿透率(Voltage-Transmittance)，外加電壓對電流(Voltage-Ampere)的變化，以及對介電係數的改變。由此我們可以看到摻入奈米雜質的液晶樣品可以降低其臨界電壓及離子效應，故吾人可以從摻入的雜質中得到更好的液晶光電反應，進而達到改善其螢幕顯像及節省能源等目的。

Nematic liquid crystal is the most common material for liquid crystal display (LCD). Some papers reported that the electro-optical properties of nematic liquid crystal could be changed with doped nanotubes. Those changes can improve the threshold voltage significantly. We plan to know if doping some different nanoparticles can change electro-optical properties in nematic liquid crystal. We use one commercial liquid crystal material MJ991597 to be our host and doped with nano-diamond powder and nano-TiO2, respectively. The concentrations are 0.1 %, 0.3 % and 0.5% for nano-diamond powder and nano-TiO2 . We measured the transmittance (voltage-transmittance curve), the ion effect (voltage-current curve), and the capacity of the liquid crystal device. We found that nano-dopants could change the electro-optical properties significantly compared with pure MJ991597. From our research, we know that the electro-optical properties can be improved by doping some nanoparticles to decrease the threshold voltage and ion effect. In other word, we can improve the performance of LCD and increase efficiency by doping nanoparticles.