臺灣博碩士論文加值系統

在本篇論文中，吾人使用銫原子與一新有機材料（Bis-OXD）共蒸鍍，形成金屬摻雜之電子傳導層，並製作成有機電激發光元件。由於銫是高原子量的鹼金族元素，不容易於有機層中擴散，所以在長期的工作下，較不亦產生淬熄現象。此外，該有機材料具有攝氏147度的高玻璃轉換溫度，有助於提升元件壽命。且其薄膜的平均表面粗糙度甚小，因此製成有機發光顯示器時，具備極低之漏電流。配合使用高反射和高導電的銀電極後，元件之驅動電壓減少2.59伏特，電流效率提高了47.3%和工作壽命提高3.14倍。
此外，我們使用一個新的紅色有機材料製作有機電激發光元件。與典型的紅色染料比較，在相同濃度下，利用此新材料製成之元件具備較高的顏色純度。此外，在元件中並未觀察到電流引發螢光淬熄之現象。由於此紅色材料具備電洞傳導之特性，於發光層及電子注入層間加上一層電洞阻擋層，可提升六倍之元件效率。

In this thesis, the OLED performance of novel cesium (Cs) doped 4,4''-bis(5-phenyl-[1,3,4]oxadiazol-2-yl)-2,2''-dinaphthylbiphenyl (bis-OXD), a metal-doped electron transport layer (MD-ETL), is reported herein. Cs is a heavy alkali atom and difficult to diffuse in an organic matrix. The metal quenching effect is therefore reduced in a long-term operation. The host material, bis-OXD, exhibits a high glass transition temperature (Tg) of 147 oC. The average roughness of the thin film is small when compared with other derivatives. The leakage current of the corresponding OLED devices is low. By using a highly reflective and conductive silver cathode, an OLED with a 2.59 V reduction in driving voltage, a 47.3% increase in current efficiency, and a 3.14 times enhancement in operation lifetime was demonstrated.
We use a new red dye organic material to fabricate an OLED. Such a device exhibits a higher color-purity as compared with that with the conventional red dopant material, 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB), under the same doping concentration. There is no current-induced fluorescence quenching on the electroluminance of the device with this red dopant material. The current efficiency of the red device can be improved by six times with insertion of a hole blocking layer between the emitting layer and electron transport layer.

Contents

Chapter 1 Introduction 1
1.1 Introduction of OLED 3
1.2 Charge Injection from the Cathode to the N-type Organic Thin-Films 7
1.3 Metal-Dopant Layer as an ETL 9
1.4 Red Doped Materials of OLED 12
1.5 Motivation 13
1.6 Thesis Organization 14
Chapter 2 Metal-doped process 29
2.1 Process Flow of OLED Fabrication 30
2.2 Setup of the Measurement System 32
2.3 Optical and Electrical Characteristics of the Metal-Doped Organic Materials 33
2.4 Device Performance of the Metal-Doped OLED 35
Chapter 3 Red Organic Light-Emitting Device 49
3.1 Optical Characteristics and Energy Diagram of the Red Dopant Material 50
3.2 Red OLED with a Conventional Device Structure 51
3.3 Red OLED with the Hole-Blocking Layer 52
Chapter 4 Conclusions 62
4.1 Conclusions and Future Works of MD OLED 62
4.2 Conclusions and Future Works of Red OLED 63

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