臺灣博碩士論文加值系統

本論文第一部分專注於苯並[k]熒蒽衍生物作為發光主體於深藍光有機發光二極體的應用，主動層使用苯並[k]熒蒽衍生物摻混於主體材中以及直接蒸鍍苯並[k]熒蒽衍生物兩種方式製作，分別討論不同衍伸物對發光頻譜的影響及發光光譜明顯改變的現象與原因。
在不同的苯並[k]熒蒽衍生物對發光頻譜的影響方面，比較在苯並[k]熒蒽主體上接上不同的取代基與調變分子共軛長度可以分別微調發光光譜波長十奈米內與數十奈米，在有機發光二極體中亦能清楚觀察到此結果。苯並[k]熒蒽衍伸物具有良好的深藍光發光特性，元件所表現出的光電性質也十分卓越。
直接蒸鍍苯並[k]熒蒽衍生物，由於發光分子間的距離較近提升了分子間交互作用的可能，苯並[k]熒蒽接上不同取代基在固態薄膜可以調變發光頻譜於深藍光到綠光之間，原來來自於不同取代基控制了激子的存活時間，短存活時間的材料維持分子本身的發光特性(深藍光)，而長存活時間造成光譜大幅度的位移(綠光)，適當的選擇取代基可以讓苯並[k]熒蒽衍伸物同時具有深藍光與綠光的發光特性。
此系統性的研究工作證明苯並[k]熒蒽衍生物應用於有機發光二極體的光電特性，製作出的深藍光元件具有良好的發光特性與穩定性。

第二部分研究疊層式元件聯接單元 (又稱電荷產生層) 界面對元件效能的影響，多數的文獻指出此電荷產生層確實能產生電子與電洞取代電極供應電子與電洞給下層與上層的發光單元，鮮少討論電荷產生後的傳輸情況對元件穩定性的研究；在此我們實驗證實改善電荷產生層內載子堆積的現象，可以大幅度提升元件效能與穩定性，指出電荷產生層內良好的傳輸效能（無電荷堆積）為影響元件效率重要的因素。

Part I:
This thesis is primarily concerned with benzo[k]fluoranthene derivatives as active layer in deep blue OLEDs, where the active layer use of two different ways, benzo[k]fluoranthene derivatives as dopant in host material and pristine benzo[k]fluoranthene derivatives film. The optical properties, electrical properties, and the reason of spectra shifted are discussing in benzo[k]fluoranthene derivatives-based OLEDs.
The fluorescent emission spectra of benzo[k]fluoranthene derivatives can be modulated by tuning the substituents and the conjugated length of the emissive core. The electroluminescence spectra of these excellent deep blue OLEDs are quite stable in any bias conditions.
Benzo[k]fluoranthene derivatives use these materials directly as the non-doped active layer to fabricate deep blue- (420-460 nm) to green- (480-580 nm) emissive OLEDs. Experimental results indicate that benzo[k]fluoranthene derivatives with different substituents in pristine films have a wide range and strong intensity of the luminescence spectra. The substituents of benzo[k]fluoranthene derivatives modulate the lifetime of the excited state and PL spectra of excitonic, excimer or both emissions in the solid state.
Part II:
Here we focus on the interface of CGLs in tandem type OLEDs. The experimental results point out there is a large barrier in CGL interface, which imply there are seriously charge accumulation after charge generation in p-type layer of CGL. This barrier seriously reduces the operating stability and increase the operating voltage of tandem OLEDs. Inserting ultra-thin high work function metal at the interface of CGL can improve the CGL that are more close to an ideal CGL. The mechanism of metal thin film modified CGLs is ascribed to the gap states of metal cluster decrease the interface barrier and reduces the charge accumulation in CGL.

中文摘要 I
Abstract II
誌 謝 III
Contents IV
List of Tables VII
List of Figures VIII
Chapter 1 Deep blue and tandem-type organic light-emitting diodes p.1
1.1 Introduction p.1
1.2 Motivation of this study p.2
1.3 Scope of this research p.3
Chapter 2 Organic semiconductors p.5
2.1 Introduction p.5
2.2 Conjugated system p.5
2.2.1 Sigma(σ) molecular orbital(MO) and hydrogen atoms p.5
2.2.2 Pi (π) MO theory - conjugation p.6
2.2.3 Aromatic compound p.8
2.2.4 Application of organic semiconductor p.9
2.3 Photochemistry of organic molecules p.11
2.3.1 The shape of absorption and PL emission spectra p.12
2.3.2 Fluorescence and Phosphorescence p.13
2.3.3 Exciton, Exciplex, and Excimer emission p.13
2.3.4 The excited state lifetime p.16
2.4 OLED operation p.16
2.4.1 Charge injection and transport p.17
2.4.2 Electroluminescence p.18
2.4.3 Current-Luminescence-Voltage characteristics p.18
2.5 Tandem type OLED p.21
2.6 Summary p.22
Chapter 3 Experimental methods p.23
3.1 Introduction p.23
3.2 Device fabrication p.23
3.2.1 Materials and device structure p.23
3.2.2 Fabrication process p.27
3.3 Electrical characteristic measurements p.33
3.3.1 Current density-Luminescent-Voltage measurement p.33
3.3.2 Capacitance-voltage (C-V) measurement p.33
3.4 Optical spectroscopy p.33
3.4.1 UV-Vis absorption spectroscopy p.33
3.4.2 Photoluminescence (PL) and excitation spectrum spectroscopy p.34
3.4.3 Time-resolved Photoluminescence (TRPL) spectrum spectroscopy p.35
3.4.4 X-ray diffraction spectroscopy p.36
3.5 Human vision and chromaticity diagram p.37
3.5.1 Emission intensity, wavelength and color sensation of the human eyes p.37
3.5.2 Color matching functions and chromaticity diagram p.39
3.6 Brightness and efficiency calculation in this study p.41
3.6.1 The relationship between EL spectrum and brightness p.41
3.6.2 Internal and external quantum efficiency p.42
3.6.3 Luminous efficiency and power efficiency p.45
3.7 Summary p.46
Chapter 4 Benzo[k]fluoranthene-based linear acenes for efficient deep blue OLEDs p.47
4.1 Introduction p.47
4.2 Simple synthesis of benzo[k]fluoranthene-based linear acenes p.50
4.3 Photo-physical characteristics of benzo[k]fluoranthene-based linear acenes p.52
4.4 Effect of substituents on energy levels of benzo[k]fluoranthene derivatives (determined electrochemical measurement) p.58
4.5 Devices structure, electrical properties and stability of benzo[k]fluoranthene derivative-based OLEDs p.60
4.6 Summary p.68
Chapter 5 Non-doped active layer for deep blue- to green- emissive organic light-emitting diodes p.69
5.1 Introduction p.69
5.2 Benzo[k]fluoranthene-based linear acenes p.72
5.3 Photoluminescence characteristics of benzo[k]fluoranthene-based linear acenes p.73
5.4 Extra emissive states by molecular packing and amorphous films by steric hindrance p.77
5.5 Excited state lifetime control the PL spectra p.78
5.6 Benzo[k]fluoranthene-based linear acenes with different substituents in deep blue to green non-doped OLEDs p.82
5.7 Summary p.87
Chapter 6 Metal interlayer in the charge generation layer of tandem OLEDs p.88
6.1 Introduction p.88
6.2 The current delay properties in CGL p.92
6.3 The influence of Ag, Au thin film in the CGL p.96
6.4 Charge generation and accumulation in CGL p.99
6.5 The mechanism of efficiency carrier transporting in CGL p.101
6.6 Summary p.102
Chapter 7 Conclusion p.104
7.1 Current progress p.104
7.1.1 Benzo[k]fluoranthene-based linear acenes, as dopants in OLED p.104
7.1.2 Non-doped benzo[k]fluoranthene derivatives-based OLED p.104
7.1.3 Carrier accumulations in the CGL of tandem OLEDs p.105
7.2 Future work p.106
7.2.1 Benzo[k]fluoranthene derivatives-based host materials for fluorescent or phosphorescent emitters. p.106
7.2.2 Confirm the functions and performance of CGL on tandem OLED p.107
References p.109
Curriculum Vitae p.116
Publication Papers p.117
Conference Papers p.117

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