層化高分子/液晶複合薄膜之直流電場效應

DC Electric Effect in Stratified Polymer-Liquid Crystal Composite Films

巫崇印(CHUNG-YIN WU)

指導教授 ： 李偉

中原大學/理學院/應用物理研究所/碩士(2008年)

https://doi.org/10.6840/cycu200900637

摘要

本論文研究重點為層化高分子/液晶雙層結構之樣品在外加直流電場作用下的光電特性；即利用自動化量測系統分別測量與電壓相依之光穿透度與電容，以及時變光穿透度與電容值，以了解離子電荷效應對樣品性能的影響。另外，本研究也嘗試在層化高分子/液晶樣品中添加奈米粒子，以觀察其相較於原始樣品之差異性。 研究結果顯示：一、層化高分子/液晶複合薄膜的直流光電特性與電壓極性息息相關；即光電特性會因為外加電壓源之正負端接於樣品之上基板（高分子層）或下基板（液晶層）而有所不同；二、作為配向層的Nylon 6存在對電荷載子選擇性吸附的現象，且傾向吸附正離子；三、在層化高分子/液晶元件中添加奈米粒子（本研究使用碳化矽與介孔分子篩MCM-41）會影響其離子電荷效應，其電壓–光穿透度遲滯寬度明顯減小，時變特性亦顯示離子電荷效應被抑制的趨勢，但只限於輸出電壓負極接於樣品之上基板的條件下，而上基板接正極時，遮蔽效應程度依然同未添加之樣品嚴重。

關鍵字

層化高分子

並列摘要

This thesis focuses on the electro-optical and electric capacitive characteristics of stratified polymer/liquid-crystal composite devices under the application of a dc electric field. The goal was set to observe the influence of the ion-charge effect on the performance of the sample by measuring the voltage- and time-dependent optical transmittance and electric capacitance using an automatic measurement system. In addition, differences were monitored between a stratified polymer/liquid- crystal cell incorporated with nanoparticles and an undoped one.
The present thesis reveals the following results: firstly, the dc electro-optical characteristics is sensitive to the polarity of the applied field; secondly, the alignment layer Nylon 6 exhibits selective adsorption, tending to adsorb the positive ion; thirdly, when the electrode covered by polymer film is negative, nanoparticles (silicon carbide and porous molecular sieves MCM-41 in this study) as a dopant influence the ion effect in the stratified devices, leading to a reduction of the voltage– transmittance hysteresis and suppression of the ionic effect as also revealed by the time-varying properties. On the other hand, doped cells retain serious ion effect when the polarity of the dc field is reversed.

並列關鍵字

liquid-crystal

參考文獻

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