臺灣博碩士論文加值系統

近年來，平面顯示器（Flat Panel Displays，FPDs）已成為光電科技產業市場主流，如TFT-LCDs、PDPs等顯示器，若能快速量產，價格可從高價位降至平價，那平面顯示器成為主流是可想而知的。但目前平面顯示器所使用之基板是以玻璃基板為主，當顯示器尺寸愈大時，重量會變重且易碎裂。此時可為之取代的是以可撓曲的材料為基板，改善以玻璃為基板的缺點，並可降低成本。倘能以可撓曲材料為基板的顯示器，目前可算是有機電致發光元件（Organic Electroemissive Devices，OEDs）最有潛力。有機電致發光顯示器與其他發展成熟的顯示器相比，有機電致發光顯示器具有高能量效率（High Power Efficiency）、高亮度（High Brightness）、響應時間短（Fast Response Time）、廣視角（Full Viewing Angle）、輕、薄，可撓曲的優點，將可取代現今平面顯示器的地位，成為顯示器的新寵兒。
有機電致發光元件發展至今，多以玻璃作為基板的有機電致發光元件，其發光效率以綠光最佳，其次是藍光，紅光，並可製出全彩有機電致發光顯示器，但是玻璃的材料先天受到限制，故本研究擬以可撓曲材料為基板，以主客系統（Host-Guest System）發光方法，並以客體濃度不同時的抑制效應（Concentration Quenching）作參數的探討，及製做出RGB三原色中高效率之紅螢光光色，並對其完成亮度、操作電壓和電流、及外部量子效率之分析研究。在製作有機電致發光元件上，本研究團隊目前已能研發出高效率之可撓式綠光有機電致發光元件，且藍光部分也已經著手進行中，今可撓式紅光有機電致發光元件是我們積極要發展的重點，以期盼完成可撓式全彩有機電致發光元件顯示器之目標。

Nowadays, there are some situations in the market. For example, FPDs （Flat Panel Displays） has become the trunk stream of the electrical and electronic industry markets. If TFL-LCDs and PDPs can be produced as many as possible with high efficiency, the high price will become the common price. So we can image that FPDs must become the trunk stream in the market of the electrical and electronic industry. But now, most substrates of FPDs are made of glass, so when the size of displays is bigger; the weight will become heavier, then it will burst easily. Now, we had better make the substrates of display by using the flexible materials to replace the glass, then we can reduce the cost. When it comes to the substrate whose material us flexible, now, OEDs （Organic Electroemissive Devices）is the most potential. And compared with other developed displays, organic light-emitting display has some advantages, such as high power efficiency, high brightness, fast response time, and full viewing angle. Besides, it is light, thin and having a big size of dimension. In addition, it can be flexible. Because of these advantages, organic light-emitting displays will replace those FPDs, and become more popular tendency.
Since organic light-emitting devices have been developed, the substrate of organic light-emitting devices, which is made of glass is with some emissive light, including green, blue and red. The radiating efficiency of green light is the best; the other ones are minor. Besides, we can make full color organic light-emitting displays, but we can’t do anything because of the restriction of the glass. Nevertheless, we have a project to make the substrate, which is made of flexible materials. By using the radiating way of Host-Guest system, various concentrations quenching result from different guest concentration, we do the studying of parameters, And then we are able to make the fluorescent red light with better efficiency of the primary colors, RGB, and analyze the completing brightness, operating voltage, operating electric current, and outer quantum. Now, our team is able to make the green light of organic light-emitting devices whose material could be flexible. In addition, we are doing some study about the blue light. Now, in order to achieve the goal that is about the flexible organic light-emitting displays, the red light of flexible organic light-emitting device is the important point that we should develop.

Publications and Preprints……………………………………………………………I
Abstract (in Chinese)…………………………………………………………………II
Abstract (in English)…………………………………………………………………IV
Gratitude…………….………………………………………………………………….VI
Contents……………………………………………………………………………..VII
Figure Captions………………………………………………………..……………….IX
Tables Captions….…………………………………………………………………….XII


Contents

第一章 緒論………………...…………………………………………………………01
Chapter 1 Introduction………………………………………………………………….03
1.1 Introduction…………………………………………………………………...03
1.1.1 The features and benefits of OLEDs………...………………………….03
1.1.2 OLED Market Opportunity……………………………………………..04
1.2 Brief History of Organic Electroluminescence……………………...………...05
1.2.1 Development of Organic Electroluminescence devices……………..….05
1.2.2 Development of Organic Materials……………………………………..06
1.2.3 Development of OLEDs Structure……………………………………...06
1.3 Motivation….…………………....………………………….…………..…….07
1.4 Organization of the Thesis……………………….……………………………08
第二章 背景理論……….……………………………………………………………..09
Chapter 2 Background Theory………………………………………………………….11
2.1 Organic Light-Emitting Diode (OLED) Theory...……………………………11
2.1.1 Fluorescent Theory………………...………………………………….11
2.1.2 Factors of Effects on Performance of OLEDs..……………………….13
2.1.3 Charge Carrier Injection, Transport and Recombination………………14
2.1.3.1 Carrier Injection………………………………………………….14
2.1.3.2 Carrier Transport…………………………………………………15
2.1.3.3 Carrier recombination……………………………………………16
2.2 The Dye Doping Technology………………………………………...………16
2.2.1 The Dopant Self–Concentration Quenching……………………………17
2.2.2 Doping dye energy transfers mechanism in the OLEDs……………….18
2.3 Calculations of Various Efficiencies…………….…………………………....20
2.3.1 Luminance Efficiency…….…………………………………………..20
2.3.2 External quantum efficiency…………...……………………………….21
2.4 Chromaticity of Dye–Doped OLEDs……………………………………….22
2.5 Characterizations of the Plastic substrates………………………………….23
2.6 The Full-Color Technology of OLEDs……………………………………..25
第三章 實驗步驟.........................................…..............................................................30
Chapter 3 Experimental Procedure……………………………….…………………….32
3.1 Preparation and Process Concepts…………………………...……….……32
3.2 Experimental Materials………………………………………………………32
3.3 Experimental System………..……………….………………………………33
3.4 Experimental Processes…………………...…………………………………34
3.4.1 Pre-Processing Cleaning………………………………………………34
3.4.2 Definition ITO Pattern………………...……………………………….34
3.4.3 OLED Devices Fabrication…………………………………………36
3.5 Measurement System………………………….…………………………..38
3.5.1 Four-Point Probe………….………………….……………………….38
3.5.2 Atomic Force Microscopy(AFM)…………………………………..38
3.5.3 Absorption(Abs.) Spectrums Measurement……………………….38
3.5.4 Photoluminance(PL) Spectrums Measurement……………….…….39
3.5.5 Current(I)-Voltage(V)-Luminance(B) Curves Measurement…………40
3.5.6 Electroluminance(EL) Spectrums Measurement…………………….40
第四章 結果與討論………………………………………………...…………………41
Chapter 4 Results and Discussions…………………………..………………..………42
4.1 Initial structure….……………………………………...….……………....42
4.2 The Optimum Thickness of Emitting Layer (For Single Dopant)…………...44
4.3 The Optimum Thickness of ETL (For Single Dopant)………………………45
4.3.1 OLEDs for Glass Substrate…………………………………………….45
4.3.2 OLEDs for Plastic Substrate…………………………………………47
4.3.3 Organic layer interface AFM analysis…………………………………47
4.4 The Optimum Doping Concentration (For Single Dopant)…………….……49
4.4.1 OLEDs for Glass Substrate…………………………………………….50
4.4.2 OLEDs for Plastic Substrate…………………………………………...51
4.5 Dual-host emitting system……………………………………………….…..53
4.5.1 OLEDs for Glass Substrate…………………………………………..54
4.5.2 OLEDs for Plastic Substrate…………………………………………...56
第五章 結論與未來工作.……………………………………………………...……...59
Chapter 5 Conclusion and Future Works……...……………………………………...61
5.1 Conclusions…………………………...…………..……………………….61
5.2 Future Works………………………………………………….……………62
Reference……………………………………………………………………………..64
Figure Captions
Figure 1. Development of organic light-emitting devices from 1997 to 2005….……...67
Figure 2. The excitation theory of OLEDs.……………………………………...…….68
Figure 3. The simple schematically of OLEDs…………………….……………..…….69
Figure 4. Carrier injection with low and high applied voltage.……………...…..…….70
Figure 5. The condition which is about exciton confined in emitting layer material….71
Figure 6. The energy distributed illustration after electron and holes combining in the organic fluorescent layer………………….....................................................72
Figure 7. The energy transfer between host and guest emitter…..……………..……......73
Figure 8. CIE chromaticity Diagram and Pe…………..…………………………...…….74
Figure 9. Architectures for implementing full-color pixels with OLEDs : (a) Side-by-side patterning of discrete R, G, and B pixels…………………………………...75
Figure 9. Architectures for implementing full-color pixels with OLEDs : (b) Filtering of a white light-emitting OLED by color passband filters…….……………..76
Figure 9. Architectures for implementing full-color pixels with OLEDs : (c) Downconversion of bule light to generate green and red light…………...…77
Figure 9. Architectures for implementing full-color pixels with OLEDs : (d)Filtering of a broad- band OLED by microcavity-based filters…….….………………...78
Figure 9. Architectures for implementing full-color pixels with OLEDs : (e) Three color-tunable pixels………………………………………………………...79
Figure 10. The molecular structures of organic material………….…………………..80
Figure 11. The schematically OLED manufacture machine………………………...…...81
Figure 12. The structure of the devices we will make.……………………….…………82
Figure 13. PL spectra of DCJTB doped in the Alq3 emitting layer with different doped concentrations.……………………………………………………………....83
Figure 14. DCJTB dopant material was doped in emitting layer to emit red light, EL spectra and FWHM for (a) glass and (b) plastic substrate………....……...84
Figure 15. The (a) luminance-voltage and (b) current efficiency curve characteristics of a glass/ITO/NPB/Alq3+DCJTB(2.5%)/LiF/Al device.……...........………......85
Figure 16. The (a) luminance-voltage and (b) current efficiency curve characteristics of a PET/ITO/NPB/Alq3+DCJTB(3.0%)/LiF/Al device.……...……………….86
Figure 17. The (a) luminance-voltage and (b) current efficiency curve characteristics of a glass/ITO/NPB/Alq3+DCJTB(2.5%)/Alq3(x nm)/LiF/Al device.……...…..87
Figure 18. The (a) luminance-voltage and (b) current efficiency curve characteristics of a PET/ITO/NPB/Alq3+DCJTB(3%)/Alq3(x nm)/LiF/Al device.…………...88
Figure 19. AFM surface roughness (Ra) of with Alq3+DCJTB films 2D and 3D pictures…………………………………………………………………….89
Figure 20. AFM surface roughness (Ra) of with Alq3 films 2D and 3D pictures………………………………………………………………….....90
Figure 21. The different doping concentration possesses different carrier hopping sites………………………………………..………………….……..……….91
Figure 22. The (a) luminance-voltage and (b) current efficiency curve characteristics of a Glass/ITO/NPB(20nm)/Alq3+DCJTB(x%)(45nm)/Alq3(20nm)/LiF(0.5nm)/Al device……………………………………….…………………………….92
Figure 23. The EL performance of the red light OLEDs with different doped DCJTB concentrations and FWHM for glass substrate…..…….…………………...93
Figure 24. The (a) luminance-voltage and (b) current efficiency curve characteristics of a PET/ITO/NPB(20nm)/Alq3+DCJTB(x%)(35nm)/Alq3(20nm)/LiF(0.5nm)/Al device.…………………………………………………….…………….…...94
Figure 25. The EL performance of the red light OLEDs with different doped DCJTB concentrations and FWHM for PET substrate……………………………....95
Figure 26. The optical absorption and PL spectra of the materials used in this work…………………..………………………………………………….....96
Figure 27. The different doping concentration possesses different carrier hopping sites…………………………..…………………………………...……..…...97
Figure 28. The (a) luminance-voltage and (b) current efficiency curve characteristics of a Glass/ITO/NPB(20nm)/Alq3+DCJTB+Rubrene(45nm)/Alq3(20nm)/LiF(0.5nm)/Al device……………………………….………………………………...98
Figure 29. The (a) luminance-voltage and (b) current efficiency curve characteristics of a Glass/ITO/NPB(20nm)/Alq3+DCJTB+Rubrene(45nm)/Alq3(20nm)/LiF(0.5nm)/Al device…………………………………………….…………….……..99
Figure 30. The (a) luminance-voltage and (b) current efficiency curve characteristics of a Glass/ITO/NPB(20nm)/Alq3+DCJTB+Rubrene(45nm)/Alq3(20nm)/LiF(0.5nm)/Al device…………………………………………………….…………100
Figure 31. The EL spectra of these devices with different concentrations of DCJTB and Rubrene for glass substrate………………………………………………...101
Figure 32. The (a) luminance-voltage and (b) current efficiency curve characteristics of a PET/ITO/NPB(20nm)/Alq3+DCJTB+Rubrene(35nm)/Alq3(20nm)/LiF(0.5nm)/Al device………………………………………………………………….102
Figure 33. The (a) luminance-voltage and (b) current efficiency curve characteristics of a PET/ITO/NPB(20nm)/Alq3+DCJTB+Rubrene(35nm)/Alq3(20nm)/LiF(0.5nm)/Al device…………………………………………………….………..…..103
Figure 34. The (a) luminance-voltage and (b) current efficiency curve characteristics of a PET/ITO/NPB(20nm)/Alq3+DCJTB+Rubrene(35nm)/Alq3(20nm)/LiF(0.5nm)/Al device……………………………………………………...…………..104
Figure 35. The EL spectra of these devices with different concentrations of DCJTB and Rubrene for PET substrate……………………………………...………….105
Figure 36. The red light OLEDs practical photographs with glass and PET substrates..106


Table Captions
Table 1. Comparison OLED to other display technologies...................…....................107
Table 2. DCJTB is used as the dopant material was doped in emitting layer to emit red light……………...…………………………………………………………..108
Table 3. The device performance of the red OLEDs at different concentrations of DCJTB and Rubrene at the optimum experimental results for glass substrate.………...……………………………………………...………..….109
Table 4. The device performance of the red OLEDs at different concentrations of DCJTB and Rubrene at the optimum experimental results for PET substrate.............…….........………………………………............................110

[1] Pope, M.; Kallmann, H.; Magnante, P. Electroluminescence in Organic Crystals. J.
Chem. Phys. 38: 2042 – 2043 (1963).
[2] C.W. Tang and S. A. VanSlyke, “Organic electroluminescent diodes,” Appl. Phys. Lett., 51, 913(1987).
[3] D.F. Williams, M. Schadt, “A simple organic electroluminescence diode,” Proc. IEEE Lett. 58, 476 (1970).
[4] C. J. Huang, 2003, Vol. 22, No 20, “Silicon Dioxide Buffer at Anode/Polymer Interface for Enhanced Brightness and Efficiency of Polymer Light-Emitting Diode”, J. of Materials Science Letters, pp. 1423-1425.
[5] C. J. Huang, Y. K. Su and Shi-Lun Wu, 2004, Vol. 84, No 1,”The Effect of Solvent on the Etching of indium tin oxide (ITO) Electrode” Materials Chemistry and Physics, pp. 146-150.
[6] C. J. Huang, and W. C. Shih, 2003, Vol. 32, No 10,”Influence of H2-and N2-ambient annealing of indium tin oxide (ITO) films on plastic substrate for organic light-emitting diode (OLED)”, J. of Electronic Materials, pp. L9-L13.
[7] http://www.kodak.com/US/en/corp/display/index.jhtml.
[8] Helfrich, W. and Schneider, W.G., Phys. Rev. Lett., 14, 229 (1965).
[9] Partridge, R.H., Polymer, 24, p.733 (1982).
[10] Burroughes, J.H., Bradley, D.D.C., Brown, A.R.,Marks, R.N., Mackly, K., Friend, R.H., Burn, P.L. and Homes, A.B., Nature, 347, 539 (1990).
[11] Braun, D. and Heeger, A.J., Appl. Phys. Lett., 58, 1982(1991).
[12] Kido, J., Kohda, M., Okuyama, M. and Nagai, K., Appl. Phys. Lett., 61, 761(1992).
[13] Gustafsson, G., Gao, Y., Treacy, G.M., Klavetter, F., Colaneri, N. and Heeger, A.J., Nature, 357, 477 (1992).
[14] Tang, C. W.; VanSlyke, S. A.; Chen, C. H. J. Appl. Phys. 1989, 65,3610.
[15] Ko, C. W.; Tao, Y. T.; Danel, A.; Krzemiñska, L.; Tomasik, P. Chem. Mater. 2001, 13, 2441.
[16] Mitschke, U.; Bäuerle, P. J. Mater. Chem. 2000, 10, 1471.
[17] H. Fröhlich, P. B. Hirsch, N. F. Mott, Martin Pope, Charles E. Swenberg, “Electronic Processes in Organic Crystals”, Oxford, 1982.
[18] 黃世哲，橫山明聰，”ITO對有機發光二極體光電特性之影響“，國立成功大學電機工程研究所八十八年碩士論文。
[19] http://www.cam.ac.uk.
[20] J. Kalinowski, J. Phys. D: Appl. Phys., 32, R179 (1999).
[21] M. Pope, and C. E. Swenberg, Electronic Processes in Organic Crystals and Polymers, Oxford University Press, New York, 379 (1999).
[22] A. A. Shoustikov, Y. You, and M. E. Thompson, IEEE Journal on Selected Topics in Quantum Electronics. 4, 3, (1998).
[23] V. Bulovic, P. E. Burrow, S. R. Forrest, “Molecular Organic Light-Emitting Devices”, Semiconductors and Electronics, 64, 255-306 (2000).
[24] P. G. Carey, P. M. Smith, M. O. Thempson, and T. W. Sigmon, Conf. Record 1997 IDRC, p.58, 1997.
[25] N. D. Young, D. J. McCulloch, and R. M. Bunn, AMLCD97, p.47, 1997.
[26] A. Stein, A. Liss, S. Fields, SID97 Deigest, p.817, 1997.
[27] E. Lueder, Mat. Res. Soc. Symp. Proc., vol. 377, p.847, 1995.
[28] S. Cucurachi, A. Rizzo, F. Sarto, S. Scaglione, Mat. Res. Soc. Symp. Proc., vol. 327, p.1529, 1996.
[29] G. A. Sack and S. F. Sartarm, Jan. p.89-98, 1975.
[30] P. E. Burrows, G. Gu. V. Bulović, Z. Shen, S. R. Forrest, and M. E. Thompson, IEEE Trans. Elec. Dev., 8, 1188(1997).
[31] H. Nakada and T. Tohma, Inorganic and Organic Electroluminescence/EL, 96, 385(1996).
[32] M. Araj, K. Nakaya, O. Onitsuka, T. Inoue, M. Codama, M. Tanaka, and H. Tanabe, Synth. Met., 91, 21(1997).
[33] J. Kido, M. Kimura, and K. Nagai, Science, 267, 1332(1995).
[34] C. W. Tang, D. J. Williams and J. C. Chang, U.S. Patent 5 294 870(1994).
[35] H. Nakamura, C. Hosokawa, and T. Kusumoto, Inorganic and Organic Electroluminescence/EL 96, Berlin, R. H. Mauch and H.-E. Gumlich, Eds. Berlin: Wissenschaft und Technik Verl., 95(1996).
[36] Seizo Miyata, “Organic Electroluminescent Material and Devices”, Ch11, Overseas Publisher Association (OPA), 1997.
[37] Quoc Toan Lea, F. Nuesch and L. J. Rothberg, E. W. Forsythe and Yongli Gao, Appl. Phys. Lett. 75(1999)1357.
[38] Q. T. Lea, E.W. Forsythea, F. Nuescha, L.J. Rothbergb, L. Yana, Y. Gao, Thin Solid Films 363 (2000) .
[39] Forster, Th. Ann. Phys. (Leipz), 2, 55 (1959).
[40] T. Forster, Discuss. Faraday Soc. 7, 27 (1959).
[41] N. J. Turo, Modern Molecular Photochemistry (Benjamin/Cummings, Menlo Park, CA), Chap. 9 (1983).
[42] J. R. Lakowicz, Principles of Fluorescence Spectroscopy (Plentum, New York), Chap. 10 (1983).
[43] Dieter K. Schroder, “semiconductor material and device characterization”, Wiley-Interscience Pubilcation, ch1, pp.2(1998).
[44] S. M. Sze, “semiconductor device physics and technology”, Wiley, Ch2, pp.37(1985).
[45] D. Sarid, Scanning Force Microscopy with Applications to electric, Magnetic, and atomic forces, Oxford University Press , New York, 1991.