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標題: | 自組織奈米結構材料於有機發光元件之應用 Investigations of Self-organized Nanostructured Materials and Their Applications in Organic Light Emitting Devices |
作者: | Yu-Tang Tsai 蔡玉堂 |
指導教授: | 吳忠幟(Chung-Chih Wu) |
關鍵字: | 自組織,有機發光二極體,偏光選擇性,點光源,出光萃取率,斜角蒸鍍法, self-organization,organic light emitting diodes,polarization,point light source,out-coupling,glancing angle deposition, |
出版年 : | 2013 |
學位: | 博士 |
摘要: | 有機發光二極體被視為下一世代的照明與顯示科技,然而目前仍有一些課題需改善與解決。舉例來說,實現具備偏光選擇性的有機發光二極體以供3D 影像顯示器使用、提升顯示器影像的光學解析度以符合高畫質的影像顯示需求、和提高元件的出光效率以達到節能需求等。
本論文中,我們藉由研究自組織奈米結構,並將其運用於有機發光二極體上,嘗試解決上述課題。自組織的定義簡單來說,就是系統內的構成物質不論受到外力的介入與否,產生自行聚集、組織成規則結構的現象。並從一個無序(disordered)的狀態轉化成一個較有序(ordered)的狀態,且具有特定的方向性與選擇性。 首先,我們探討具液晶特性之磷光有機發光材料運用於有機發光二極體的偏光選擇機制。所選之液晶分子經由微弱的作用力引導產生特定的排列結構,此一具非等向光學特性的自組裝奈米結構薄膜能有效操控電致發光元件的偏光選擇性。藉由了解此一機制,能夠更有效控制與改良具偏光選擇性的有機發光二極體。 接著,我們探討具有自組裝特性之有機發光奈米球殼之基本光電特性,並將其使用於有機發光二極體結構上。研究結果驗證了自組裝有機發光奈米球殼在電致發光下為接近光學繞射極限的單一點光源,有機會經由更進一步地研究來實現高解析度有機發光二極體顯示器。 最後,我們使用斜角蒸鍍法(GLAD)來製作可調控光學特性之奈米結構薄膜。斜角蒸鍍法是利用原子在沉積過程中蒸鍍源和基板有傾斜角的情況製作而成。此種薄膜可以依據不同的成長條件,而有不同的光電特性及幾何結構。我們將其應用在有機發光二極體上,以達成各膜層光學折射率之匹配。此一光學匹配經驗證確實能有效提高有機發光二極體出光效率。 總結來說,具有自組裝特性之奈米結構未來具有相當潛力可廣泛的應用於各式先進有機發光二極體上或光電元件上。 Organic light emitting diodes (OLEDs) have attractive features for next-generation display applications. However, there are still some issues needed to be overcome. For examples, realizing the polarized OLEDs for of 3D displays, improving the optical resolution of OLED displays for high-definition images, and improving the optical out-coupling efficiency of OLEDs for achieving higher energy efficiency. In this dissertation, to solve above issues, we study a series of self-organized nanostructures for use in OLEDs. With self-organization, the components in a system will self-cluster and self-organize in more ordered structures, no matter with or without external force. The transition from disordered to ordered situations usually induces orientational and anisotropic characteristics in materials. First, we investigate the polarized and alignment mechanism of a series of organic phosphorescent materials with liquid-crystal properties for polarized OLEDs. The molecules with liquid-crystal properties can be guided to follow specific orientation by rubbing and annealing treatments. In fact, in these thin films, self-assembly nano-structures occur with optically anisotropic properties that can be used to control polarizations of OLEDs. Understanding the mechanisms is useful to further improve the polarization of OLEDs. Then, we study the basic optical/electrical properties of self-assembly organic emitting nanospheres and further apply them into OLEDs. Our results confirm that each self-assembly nanosphere in electroluminescence devices can be viewed as a point light source, with a resolution approaching the optical diffraction limit. Their promising optoelectronic properties have the potential for realization of high-resolution OLED displays. Finally, indium tin oxide (ITO) films with tunable optical properties by self-assembly nanostructures are fabricated by glancing angle deposition (GLAD). The GLAD technique makes use of oblique-angle deposition from the evaporation source to the substrate. Tunable optical and electrical properties, such as the refractive index,optical transmission, and sheet resistance, could be obtained by different fabrication conditions. These optically tunable ITO films are utilized to achieve index-matching for layers in OLEDs. Results of this study show that the outcoupling efficiency of OLEDs can be improved significantly by using index-matching ITO. In summary, in this dissertation, we have successfully developed a series of self-organized nanostructures and materials for OLEDs. They indeed show the potential for the use in specialized OLEDs or for improving OLED characterizations. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/58787 |
全文授權: | 有償授權 |
顯示於系所單位: | 光電工程學研究所 |
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