臺灣博碩士論文加值系統

有機發光材料有著許多無機發光材料所沒有的優越性質，且易於以較簡單的溶液製程來做各種面積的加工成膜，在紅綠藍三原色都已有相當成熟可用的發光材料。膽固醇液晶具有週期性螺旋結構，因此具有選擇性反射光的特性，且易因外在的力場而改變結構，可透過外加應力改變膽固醇液晶的反射波段，其螺距的大小與溫度的高低有相當大的關聯，大部分的膽固醇液晶會隨著溫度上升而螺距逐漸減少，使反射波段往短波長區域移動。
本研究以溶液製程的旋轉塗佈法將有機材料製作成均勻的有機發光薄膜，並結合可溫控改變反射波段的膽固醇液晶作成光色可調控之膽固醇液晶元件。以氦鎘雷射所發出的波長325 nm紫外雷射光當作激發光源，有機發光薄膜主要是利用主-客發光體能量轉移特性來得到介於紅色和綠色之間的螢光，並由親手性分子產生合成白光所需的藍光，最後透過改變溫度使膽固醇液晶的反射波段產生位移，藉以反射掉部分相對應之色光，使此光色可調控照明元件可得到白光和其它多種色光。

Organic materials have many excellent properties not found in inorganic compounds, and are ideal for the fabrication of large area films by simple solution process. There are many organic materials available for the primary colors of light, red, green, and blue. Cholesteric liquid crystal has a periodic helical structure, leading to a selective Bragg reflection. The helical structure can be influenced by various external stimuli. The length of the helical pitch is closely related to temperature. As the temperature increases, the pitch decreases, and the reflection band is shifted to the short- wavelength region.
In this study, organic guest-host emitting films were fabricated by spin coating process. Based on the controllability of the helical pitch, cholesteric liquid crystals were combined with the organic films to achieve temperature-controlled color tunable light-emitting devices. A 325 nm He-Cd laser was used to excite the organic films. Through Förster energy transfer, the pump light absorbed by the host material transfers to the guest dopant, enabling a broadband emission from green to red.The cholesteric liquid crystals were excited simultaneously by the He-Cd laser to emit blue light. The reflection band of the cholesteric liquid crystals was tuned by changing temperature and color tunable illumination devices were obtained.

摘要................................................................................................................................Ⅰ
Abstract..........................................................................................................................Ⅱ
誌謝................................................................................................................................Ⅲ
目錄................................................................................................................................Ⅳ
圖目錄............................................................................................................................Ⅶ
表目錄............................................................................................................................Ⅹ
第一章、緒論..................................................................................................................1
1-1、前言.....................................................................................................................1
1-2、有機發光材料.....................................................................................................2
1-2-1、小分子有機紅光材料.................................................................................2
1-2-2、小分子有機綠光金屬錯合物.....................................................................3
1-2-3、高分子有機藍光共軛聚合物.....................................................................4
1-2-4、藍光膽固醇液晶材料.................................................................................5
1-3、液晶簡介.............................................................................................................5
1-3-1、液晶的起源.................................................................................................5
1-3-2、何謂液晶.....................................................................................................6
1-3-3、液晶的分類.................................................................................................7
1-3-4、液晶的光學異向性與雙折射性...............................................................18
1-3-5、液晶連續彈性體理論...............................................................................20
1-3-6、溫度對向列型液晶的影響.......................................................................21
第二章、理論................................................................................................................22
2-1、發光系統與相關機制.......................................................................................22
2-1-1、光致發光原理.........................................................................................22
2-1-2、主-客發光體間的能量轉移....................................................................23
2-2、膽固醇液晶.....................................................................................................26
2-2-1、膽固醇液晶的光學特性..........................................................................26
2-2-2、溫度對膽固醇液晶螺距的影響..............................................................28
2-3、CIE標準色度系統.........................................................................................29
第三章、樣品製作與實驗架設......................................................................................33
3-1、材料介紹.........................................................................................................33
3-2、樣品製作.........................................................................................................36
3-2-1、玻璃裁切及清洗......................................................................................36
3-2-2、發光膜製作.............................................................................................37
3-2-3、具水平配向膜之玻璃基板製作.............................................................38
3-2-4、膽固醇液晶配製.....................................................................................39
3-2-5、光色可溫控之膽固醇液晶元件製作......................................................39
3-3、實驗架設.........................................................................................................40
3-4、元件發出螢光之CIE標準色度座標計算.....................................................43
第四章、結果與討論......................................................................................................44
4-1、有機發光材料PVK、Alq3、DCM的吸收測量.............................................44
4-2、發光膜的螢光測量.........................................................................................44
4-3、膽固醇液晶樣品於不同溫度下的反射頻譜測量.........................................48
4-4、光色可溫控之CLC元件於不同溫度下的螢光測量...................................49
第五章、結論..............................................................................................................54
參考文獻......................................................................................................................55

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