臺灣博碩士論文加值系統

由於其可撓性、可彎曲性、耐衝擊性…等好處，OLED軟性顯示器在科技發展上越來越重要。但OLED出光效率低落一直是個待解決的問題，以前有許多方法包括減少淬熄效應、減少基板與空氣間的全反射效應以及減少波導模態…等。但這些方法之中有許多是會讓OLED元件失去軟性顯示器的特質，變成不可撓的元件。近來在Nature Photonics中有一篇改善OLED出光效率的論文既可兼顧軟性顯示器的特質也可增進OLED出光效率，其相當高的效率提升令我們想要探討其深入元件機制。
在本論文中， 我們仿照Nature Photonics論文中的元件結構，作了一系列的模擬計算。發現同結構下，我們所計算的發光效率增益只有1.455倍，不及其論文所提及的兩倍。此結果差異可能是改變元件結構所造成的電性提升，使得OLED發光效率額外增益許多，超出光學模擬可以解釋的範圍。

Due to their various features and merits, flexible OLED displays are becoming more and more important. Yet, the low optical out-coupling efficiency of OLED devices is still an issue. There are some solution like reducing the quench effect, reducing the total internal reflection between substrate and air, and reducing the waveguilde modes…etc. Yet, some of them will change the OLED flexible feature. Recently, page in Nature Photonics provides a method to improve the optical out-coupling efficiency and keeps the OLED flexible feature. Here, we want to investigate their mechanism by simulation.
In this study, we based on their structures, we conducted a series of calculation. Our calculation indicates only a 1.455Xefficiency enhancement, much lower than their 2X enhancement. The discrepancy of the results may be due to improved electrical properties in their device structures, beyond the pure optical effects.

摘要 i
ABSTRACT ii
CONTENTS iii
Chapter 1 緒論 1
1.1 有機發光二極體發展 1
1.2 OLED之出光議題 3
1.2.1減少淬熄效應 3
1.2.2減少全反射 3
1.2.3減少波導效應 4
1.3 具有光學耦合層之下發光微共振腔有機發光元件 5
1.4 論文架構 8
Chapter 2 有機發光元件光學模擬 17
2.1 前言 17
2.2 有機發光元件光學模擬原理 18
2.2.1 OLED中的光學效應………………………………………………...18
2.2.2光學模擬的基礎原理………………………………………………...18
2.2.3光學模型之輸入與輸出 19
2.3 模擬結構 21
Chapter 3 結果與討論 24
3.1 前言 24
3.2 標準下發光元件計算結果 24
3.3 具高折射率光學耦合層之微共振腔下發光元件計算結果 26
3.4 討論 28
Chapter 4 總結 45
參考文獻 46

[1]M. Pope, H. Kallmann, and P. Magnante, Electroluminescence in organic crystals, J. Chem. Phys. 38 (1963) 2042-2043.
[2]W. Helfrich and W.G. Schneider, Recombination radiation in anthracene crystals, Phys. Rev. Lett. 14 (1965) 229-231.
[3]F. Lohmann and W. Mehl, Dark injection and radiative recombination of electrons and holes in naphthalene crystals, J. Chem. Phys. 50 (1969) 500-506.
[4]M. Kawabe, K. Masuda, and S. Namba, Electroluminescence of green light region in doped anthracene, Jpn. J. Appl. Phys. 10 (1971) 527-528.
[5]J. Kalinowski, J. Godlewski, and R. Singnerski, Mol. Cryst. Liq. Cryst. 33 (1976) 247.
[6]P.S. Vincett, W.A. Barlow, R.A. Hann, and G. G. Roberts, Electrical conduction and low voltage blue electroluminescence in vacuum-deposited organic films, Thin Solid Films 94 (1982) 171-183.
[7]C.W. Tang and S.A. VanSlyke, Organic electroluminescence diodes, Appl. Phys. Lett. 51 (1987) 913-915.
[8]C.W. Tang, S.A. VanSlyke, and C.H. Chen, Electroluminescence of doped organic thin-films, J. Appl. Phys. 65 (1989) 3610-3616.
[9]D.L. Dexter, A theory of sensitized luminescence in solids, J. Chem. Phys. 21 (1953) 836-850.
[10]J.H. Burroughes, D.D.C. Bradley, A.R. Brown, R.N. Marks, K. Mackay, R.H. Friend, P.L. Burns, and A.B. Holmes, Light-emitting diodes based on conjugated polymers, Nature 347 (1990) 539-541.
[11]C. C. Wu, C. W. Chen, C. L. Lin, and C. J. Yang, Advanced organic light-emitting devices for enhancing display performances, J. Display Technol. 1 (2005) 248-266.
[12]B. W. D’Andrade and S. R. Forrest, White organic light-emitting devices for solid-state lighting, Adv. Mater. 16 (2004) 1585-1595.
[13]V. Bulovic, V. B. Khalfin, G. Gu, P. E. Burrows, Weak microcavity effects in organic light-emitting devices, Phys. Rev. B 58 (1998) 3730.
[14]J.J. Shianga, A.R. Duggal, Organic light-emitting devices for illumination quality white light, J. Appl. Phys.. 95 (2004) 2880
[15]S. Moller, S. R. Forrest, Improved light out-coupling in organic light emitting diodes employing ordered microlens arrays, J. Appl. Phys. 91 (2002) 3324.
[16]M. H. Lu, J. C. Sturm, Optimization of external coupling and light emission in organic light-emitting devices: modeling and experiment, J. Appl. Phys. 91 (2002) 595.
[17]T. Tsutsui, M. Yahiro, H. Yokogawa, K. Kawano, M. Yokoyama, Doubling coupling-out efficiency in organic light-emitting devices using a thin silica aerogel layer, Adv. Mater. 13 (2001) 1149.
[18]H. J. Peng, Y. L. Ho, X. J. Yu, H. S. Kwok, Enhanced coupling of light from organic light emitting diodes using nanoporous films, Appl. Phys. 96 (2004) 1649.
[19]Z.B.Wang, M.G. Helander1, J. Qiu, D.P. Puzzo, M.T. Greiner, Z.M. Hudson, S. Wang, Z.W. Liu, Z.H. Lu, Unlocking the full potential of organic light-emitting diodes on flexible plastic, Nature Photonics 5 (2011) 753–757
[20]A. Mikami, & T. Koyanagi, high efficiency 200-lm/W green light emitting organic devices prepared on high-index of refraction substrate, SID Symposium Digest of Technical Papers 40 (2009) 907–910.
[21]S. Mladenovski, K .Neyts, D. Pavicic, A. Werner, C, Rothe, Exceptionally efficient organic light emitting devices using high refractive index substrates, Opt. Express 17 (2009) 7562–7570.
[22]S. R. Forrest, The path to ubiquitous and low-cost organic electronic appliance son plastic, Nature 428 (2004) 911–918.
[23]A. Dodabalapur, et al, Physics and applications of organic microcavity light emitting diodes, J. Appl. Phys. 80 (1996) 6954–6964.
[24]M. G. Helander, et al, Oxidized gold thin films: an effective material for high performance flexible organic optoelectronics, Adv. Mater. 22 (2010) 2037–2040.
[25]Z. B. Wang, et al, Direct hole injection in to 4,4′-N,N′-dicarbazole-biphenyl: a simple pathway to achieve efficient organic light emitting diodes, J. Appl. Phys. 108 (2010) 024510.
[26]H. Ishii, K. Sugiyama, E. Ito, & K, Seki, Energy level alignment and interfacial electronic structures at organic/metal and organic/organic interfaces, Adv. Mater. 11 (1999) 605–625.
[27]Z. B. Wang et al, Highly simplified phosphorescent organic light emitting diode With > 20% external quantum efficiency at > 10,000 cd/ , Appl. Phys. Lett. 98 (2011) 073310.
[28]M. G. Helander, Z. B. Wang, M. T. Greiner , J. Qiu, Z. H. Lu, Substrate dependent charge injection at the V2O5/organic interface, Appl. Phys. Lett. 95 (2009) 083301.
[29]M. G. Helander, Z. B. Wang, J. Qiu, Z. H. Lu, Band alignment at metal/organic and metal/oxide/organic interfaces, Appl. Phys. Lett. 93 (2008) 193310.
[30]國立台灣大學光電工程學研究所碩士論文，指導教授吳忠幟博士，研究生江獲先撰，91年6月。