偶氮染料及矽奈米粒子摻雜液晶之特性研究及其應用

本實驗將偶氮染料及奈米粒子摻雜進液晶中並將其製作成混合排列的樣本(Hybrid-aligned nematic cell；HAN cell)，利用奈米粒子可經由直流電壓操控的電泳特性，使奈米粒子累積在樣本的水平配向側或是垂直配向側，並探討樣本在這兩種情況下照光吸附後所產生的特性。從實驗結果得知，當樣本施加一個脈衝直流電壓使奈米粒子累積在垂直配向側，此時液晶排列為Hybrid結構並對水平配向側照光，並且在照完光後對樣本施加一脈衝直流電壓來驅使奈米粒子游向水平配向側，我們發現吸附區的液晶排列狀態並不會受到奈米粒子的影響發生改變，而是維持在吸附後的排列狀態。當施加一個脈衝直流電壓使奈米粒子累積在水平配向側，此時樣本會因為水平配向側的液晶受到奈米粒子的穩固而呈現垂直排列的狀態，並且在此情況下對該側照光後可發現，對照完光的樣本施加一個反向的脈衝直流電壓後，吸附區並不會變回原來的混合排列，而是維持在垂直排列的狀態。我們分別利用了上述的兩種特性製作出半反穿顯示器(transflective LC display)以及相位光柵(phase grating)，並且此相位光柵可使用動態或是多穩態的操作方式來調控繞射效率。

關鍵字

液晶；偶氮染料；奈米粒子；多穩態；電泳；吸附

並列摘要

In this study, we researched the electro-optical characteristics of silica nanoparticle and azo dye-doped liquid crystals (LCs) with hybrid aligned structure. The experimental process was as follows. Firstly, an external DC pulse-voltage was applied to the sample to control silica nanoparticles to accumulate on the substrate surface. Then, a diode-pumped solid-state (DPSS) green laser was adopted to irradiate the rubbing side of the LC cell and to induce the adsorption of azo dye molecules on the surface of the illuminated substrate. The results showed that the stability of the memory state of the sample decreased when LC molecules were hybridly aligned due to the accumulation of silica nanoparticles on the vertical aligned substrate side during the illumination duration. It was considered that the adsorption of azo dye molecules changed the surface energy of the substrate, and reduced the stability of the memory state. This characteristic was applied to fabricate a single cell-gap transflective LC display. When silica nanoparticles were accumulated on the homogeneously aligned substrate side during the illumination duration, the memory state of the sample was frozen. The reason was that azo dye molecules adsorb on the aggregated silica nanoparticles, and suppressed the electrophoretic effect. Therefore, the LC molecules remained to orient vertically. This result was also applied to fabricate a dual mode (dynamic and multi-stabe) phase grating.

並列關鍵字

liquid crystal ； azo dye ； nanoparticles ； multi-stability ； electrophoretic ； adsorption

參考文獻

[1]W.-Z. Chen, Y.-T. Tsai, and T.-H. Lin, 2009, "Photoalignment effect in a liquid-crystal film doped with nanoparticles and azo-dye", Applied Physics Letters, 94, 201114, May.

[2]A.Y.-G. Fuh, C.-Y. Huang, C.-K. Liu, Y.-D. Chen,and K.-T. Cheng, 2011, "Dual liquid crystal alignment configuration based on nanoparticle-doped polymer films”, Optical Society of America, 19, 11825–11830, June.

and electrically tunable liquid crystal Fresnel lenses based on photoalignment in dye-doped liquid crystals", Journal of the Society for information Display. 18, 572–576, June.

[4]W. Lee, C.-Y. Wang, and Y.-C. Shih, 2004, "Effects of carbon nanosolids on the electro-optical properties of a twisted nematic liquid-crystal host", Applied Physics Letters, 85, 513–515, July .

[5]C.-Y. Huang, H.-C. Pan, and C.-T. Hsieh, 2006, "Electrooptical properties of carbon

國際替代計量

偶氮染料及矽奈米粒子摻雜液晶之特性研究及其應用

未授權

主題瀏覽