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研究生: 葉書瑋
Yeh, Shu-Wei
論文名稱: 白光有機發光二極體發光層之改良
Improvement of emitting layer in white organic light emitting devices
指導教授: 許渭州
Hsu, Wei-Chou
學位類別: 碩士
Master
系所名稱: 電機資訊學院 - 微電子工程研究所
Institute of Microelectronics
論文出版年: 2008
畢業學年度: 96
語文別: 英文
論文頁數: 58
中文關鍵詞: 白光有機發光二極體發光層效率
外文關鍵詞: WOLEDs, emitting layer, efficiency
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  • 於本文中,使用共蒸鍍的技術應用於藍光有機發光材料TBADN 以及黃色的染色有機材料Rubrene製作高效率以及高色穩定度的白光有機發光元件(WOLEDs)。在製作的同時也發現在藍光材料TBDAN 的發光頻譜以及Rubrene的吸收頻譜有相對高的重疊性。
    首先試圖得到最佳化白光有機發光元件的結構,其結構依序如下ITO/NPB(70 nm)/TBDAN:0.5% Rubrene(30 nm)/Alq3(10 nm)/LiF(1 nm)/Al(120 nm),在外加偏壓10 伏特可以達到17,810 (cd/m2)而在4伏特可以達到4.26 (cd/A)的效率。
    雖然加入電洞阻隔層會提升白光有機發光二極體的電流效率至5.47(cd/A),但產生顏色偏黃的現象而座標為(0.39, 0.42)。為了改善顏色偏黃的問題,改變黃光掺雜材料的厚度,避免載子直接注入Rubrene,在9伏特偏壓下CIE座標為(0.34,0.34)。在發光層之間加Alq3中間層,為了延遲載子傳遞的時間,提升高電流密度下的效率,最後比較中間層為BCP和TPBi,中間層為TPBi的元件有最佳結果。
    最佳的結構為ITO/NPB(70 nm)/TBADN(5 nm)/TBADN:0.5% Rubrene(10 nm)/TPBi(5 nm)/TBADN:0.5% Rubrene(10 nm)/TBADN (5 nm)/BCP(10 nm)/Alq3(10 nm)/LiF(1 nm)/Al(120 nm)在外加偏壓10伏特可以達到 11,770 (cd/m2)而在4.5伏特可以達到6.43 (cd/A)的電流效率而外加偏壓9伏特色度座標為(0.32, 0.32)。在不加入任何藍光掺雜材料的前提下,提升白光有機發光元件的效率,並同時維持白光的純度。

    We use the co-vaporizing skills in blue organic material TBADN and yellow dyeing organic material Rubrene to achieve high efficiency and color stability white organic light emitting devices (WOLEDs). We also discover high overlapping between emitting photoluminescence of TBDAN and absorption of photoluminescence of Rubrene.
    At first, we try to optimize the best white light emitting device structure whose layer in order as ITO/ NPB(70 nm)/TBDAN: 0.5% Rubrene (30 nm)/Alq3 (10 nm)/LiF (1 nm)/Al(120 nm), and we obtain the highest luminescence and efficiency which are 17,810 (cd/m2) at 10 applied voltage and 4.26(cd/A) at 4 applied voltage.
    Although adding the hole blocking layer ensures that the WOLEDs using TBADN as a blue host has a current efficiency of 5.47 cd/A in Device 2, but yellow-shift phenomenon occurs with CIE coordinate (0.39, 0.42).We change the doping thickness of Rubrene to solve the yellow-shift problem and avoid the direct injection of carriers to Rubrene with the CIE coordinate (0.34, 0.34). We also add the middle layer of Alq3 between emitting layer to delay the passing time of carriers and enhance efficiency at high current density. And then, we also compare the middle layer of Alq3 with BCP and TPBi. We increase the efficiency of WOLEDs without adding a blue dopant while simultaneously maintaining the color purity.
    Finally, the structure of optimization device is ITO/NPB(70 nm)/TBADN(5 nm)/
    TBADN:0.5%Rubrene(10 nm)/TPBi(5 nm)/TBADN:0.5%Rubrene(10 nm)/TBADN(5 nm)/BCP(10 nm)/Alq3(10 nm)/LiF(1 nm)/Al(120 nm). We obtain the highest luminescence and efficiency which are 11,770 (cd/m2) at 10 applied voltage and 6.43 (cd/A) at 4.5 applied voltage and CIE (0.32, 0.32) at 9 applied voltage.

    Abstract (Chinese) Abstract (English) Table Captions Figure Captions Chapter 1 Introduction 1 Chapter 2 Organic Light-Emitting Device 3 2-1 The Organic Light-emitting Theorems 3 2-2 Mechanism of emitting light 5 2-3 Measurements of light emission 7 2-4 Materials of anode and cathode 9 2-5 Design of Organic Light-emitting Device 10 2-6 Blue Organic Light-emitting Device 10 2-7 White Organic Light-emitting Device 11 Chapter 3 Fabrication of Organic Light-Emitting Device 12 Device Fabrication Process 12 3-1 Pre-clean ITO Glass 12 3-2 ITO Pattern Etching 13 3-3 UV Ozone Treatment 13 3-4 Thermal organic vaporizing 14 Chapter 4 Experimental Results 15 4-1 Device Structure 15 4-1-1 Device Structure(Single Emitting Layer) 15 4-1-2 Device Structure(Dual Emitting Layer) 16 4-1-3 Device Structure(Modified Emitting Layer) 17 4-2 Results 19 4-2-1 Comparison of single emitting layer devices 19 4-2-2 Comparison of dual emitting layer devices 20 4-2-3 Comparison of modified dual emitting layer devices 20 Chapter 5 Conclusion 21 Reference 22

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