摘要:本計畫是擬使用高解析液晶薄膜比熱儀,光反射儀,光學紋理觀測系統以及改裝型穿透式電子顯微鏡來研究諸多種類之液晶薄膜的熔化現象,前期計畫已成功建造以上量測儀器並使其運轉正常,同時亦有豐富的研究成果出現。此次申請的研究計畫中將承續並開展旋光型與彎型液晶薄膜材料之結構分析研究,以期發現具有不同對稱性的新液晶相位,同時建立相關模型以瞭解前瞻性液晶材料排列與結構上變化的成因,實驗結果可提供合成化學家在合成材料時所需的重要參考依據。在學術上,實驗所得之相關結果可使我們進一步瞭解不同前瞻性液晶材料發生相轉換時之臨界行為,同時其結果亦可用來比對許多現存的物理模型。
在液晶應用的領域中,我們過去成功開展了摻雜奈米粒子於液晶中的許多研究,例如摻雜絕緣奈米粒子可降低離子電流但卻能維持液晶之電壓保持率,此方面的結果已獲得產業界的高度重視,其他工作還包含藉由液晶調控金奈米粒子的transverse 與longitudinal 表面電漿模式,我們亦首度觀察到以電場驅動混雜於液晶中奈米金棒狀粒子,其PL 光譜產生紅移與藍移之物理機制與成因,此外我們首度以電場控制一維奈米半導體在液晶材料中之偏極現象,這使得液晶與一維半導體混合之材料成為一可受電場控制之Smart Optoelectronic Device,這些結果都獲得學術界高度的重視,此外,我們從事異質接面有機太陽能電池研究,藉由取代傳統電洞傳遞層之材料,我們成功改善此類太陽能電池之效率。我們將在本計畫中繼續進行這些研究,並同時開展本計畫所列出的各項新研究子題,以期能得到更多豐盛的成果。
另外,在利用液晶與其他軟物質高分子特性的相關領域中,我們在奈米液晶配向、軟性微影技術、與軟基板微陣列透鏡的應用上也做出貢獻,其中我們成功開展兩項新穎的液晶分子配向技術,以及能製作自組裝的軟基板微陣列透鏡用於大面積可撓式之液晶顯示元件,同時我們也發明了一種能製作複雜且大面積奈米圖案的熱拉引微影技術,這種利用熱拉引的微影方法與普林斯頓大學Prof. S. Y. Chou 發明的Nano Imprinting 有所不同,它不需要脫膜的過程所以其操作更為簡單,且拉引出來的奈米圖案其邊緣非常整齊,相信這項技術未來會有很多的應用性。在本次所提的計畫中我們會繼續拓展這項技術在液晶光電顯示與其他領域方面的應用,例如在微流通道、生物晶片、與應用在有機電子和光電科技等領域應該都有相當高的應用價值。
Abstract: This project is planned to use high-resolution ac calorimeter, optical reflectometer,
polarized optical microscope, and transmission electron microscope (TEM) to study the phenomena of phase transitions in LC thin film system. Our goal in this project is to discover new frontier LC phase and to establish some related models that can explain how the structure, the thermal property, and type of optical textures of studied LC films are affected by the geometry of the LC molecule, the magnitude of spontaneous polarization, and the location and number of chiral center on the LC molecule. The obtained experimental data can not only provide us further realization on the critical behaviors of different phase transitions in some LC thin films, but also help us for the understanding of the physical mechanism of reduced-dimensional system. In addition, our experimental result can be used to check many different exisiting physical models on critical phenomenon.
In the field of LCD applications, we have successfully carried out many researches
regarding nanoparticles doping in LCs, such as doping insulating nanoparticles in LC can not only reduce the ion current, but also maintain the high voltage-holding ratio in LCD. This result has received great attention in LCD industry. Other doping works include the regulation of gold nanorods using LCs. We observe the transverse and longitudinal surface Plasmon modes tuned by LCs upon applying the electric field. We also first realize the physical mechanism of PL spectra shift due to the interaction between gold nanorods and anisotropic LC environment. In addition, we first use LCs by applying electric field to align 1D semiconductor nanorods to produce a polarization. This makes the mixture of LCs and 1D semiconductor nanorods controllable by the electric field and become a smart optoelectronic device. These results have received a high degree of academic attention. In addition, we conducted research on heterojunction organic solar cell, we successfully improve the conversion efficiency by means of CF3-silane modification using soft imprinting fabrication
technique to replace conventional PEDOT:PSS layer. In this project, we will continue these studies and also carry out new sub-titles listed in this project, in order to get more fruitful results.
Further, in the field of soft matter and polymer, we have made some contributions in LC alignment, soft lithography, and flexible polymer microlens array. We have successfully launched two new LC alignment techniques. Recently, we fabricated a flexible self-assembled microlens array used for large area flexible LCD. At the same time, we invented an unique thermal drawing lithography (TDL) which can produce a complex and large-area nanopatterns. This technique is different from the nano-imprinting technique by Prof. S. Y. Chou. The TDL dose not require the difficult demolding process so it can easily produce nanopatterns without
damage. Especially, the edge of nano patterns obtained by TDL is always very clean and neat. Hence, we believe the TDL will have many useful applications in the near future. In the project topics we proposed here, we will continue to expand this TDL technique in the LCDs and other research areas, such as microfluidics, biochips, and their applications in organic electronics and optoelectronics should also have a considerable high value.