含奈米雜質之水平排列液晶元件的光電特性

Electro-Optical Properties of Homogeneous Liquid-Crystal Cells Doped with Nanosolids

高迦翔(Jia-Shiang Gau)

指導教授 ： 李偉

中原大學/理學院/應用物理研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500030

摘要

摘 要
本論文旨在研究摻雜碳奈米固體（碳60或碳奈管）的水平排列液晶盒在直流或交流電壓下的光電特性，以了解在相關系統中離子電荷效應對樣品性能所產生之影響。研究中發現在外加直流電壓作用下，180°水平排列液晶盒中摻雜奈米級碳材會影響其離子電荷效應行為，且摻雜極微量的碳奈管能有效地降低液晶盒的閾值電壓；而在0°水平排列液晶盒中，我們發現碳奈管的添加並不會降低液晶盒的閾值電壓。

另外，在外加交流電壓下，離子效應並不明顯；相較於直流電壓，180°水平排列液晶盒之閾值電壓均有降低，且0°水平排列液晶盒之閾值電壓也有大幅度明顯變小；但不論是180°或0°液晶盒，三種液晶樣品（E7、E7/C60、E7/CNT）之閾值電壓所差無幾。

關鍵字

液晶 ； 碳奈管

並列摘要

Abstract
This thesis focuses on electro-optical effects in homogeneous cells of pristine and nanosolid（C60 or Carbon nanotubes）-doped nematic liquid crystal in the presence of dc or ac voltage. The purpose is to observe the hysteresis characteristics that manifests the charge-retention effect in homogeneous liquid-crystal cells. Experimental evidence indicates that a nanoscale carbon dopant can affect the behavior of an antiparallel-aligned liquid crystal cells in terms of ion-charge effects and that doping with nanotubes can effectively reduce the dc threshold voltage. On the other hand, parallel-aligned liquid-crystal cells do not posses a lower dc threshold voltage by doping carbon nanotubes.

Under the application of an ac voltage, all cells exhibit unobserved ion-charge effect. In comparison with those operated by dc voltage, the threshold voltage of antiparallel-aligned cells is apparently lower and the threshold voltage of parallel-aligned cells is even more greatly lowered. The difference between threshold values of doped and undoped cells is small.

並列關鍵字

carbon nanotubes ； liquid crystal

參考文獻

[10] 胡正中、李偉，《含雜質向列型液晶之實驗光譜》，《中原學報》， 29，213–217 (2001)。

[3] Wei Lee and C.-S. Chiu, “Observation of self-diffraction in nematic liquid crystals doped with carbon nanotubes,” Optics Letters 26, 521–523(2001).

[4] W. Lee and S.-L. Yeh, “Optical amplification in nematics doped with carbon nanotubes,” Applied Physics Letters 79, 4487–4490 (2001).

[5] W. Lee, C.-Y. Wang, and Y.-C. Shih, “Effect of carbon nanosolids on the electro-optical propertyes of a twisted nematic liquid-crystal host,” Applied Physics Letters 85, 513–515 (2004)

[6] R. Saito, M. Fujita, G. Dresselhaus, and M. S. Dresselhaus, “Electronic structure of chiral graphene tubules,” Applied Physics Letters 60, 2204–2206 (1992).