(3.235.25.169) 您好!臺灣時間:2021/04/17 20:16
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果

詳目顯示:::

我願授權國圖
: 
twitterline
研究生:周仕賢
研究生(外文):SHIH-HSIEN CHOU
論文名稱:利用同步輻射光電子能譜研究Ag/LiF/PFO介面反應對高分子有機發光二極體光電特性之影響
論文名稱(外文):Using X-ray Photoemission with Synchrotron Radiation to Study Interface Reaction between Ag/LiF/Poly(9,9-dioctylfluorene)(PFO) for Variations of Electro-Optical Characteristics in Polymer Light Emitting Diodes
指導教授:劉國辰
指導教授(外文):KOU-CHEN LIU
學位類別:碩士
校院名稱:長庚大學
系所名稱:光電工程研究所
學門:工程學門
學類:電資工程學類
論文種類:學術論文
論文出版年:2007
畢業學年度:95
語文別:英文
外文關鍵詞:photoemissionAg/LiF
相關次數:
  • 被引用被引用:0
  • 點閱點閱:184
  • 評分評分:系統版面圖檔系統版面圖檔系統版面圖檔系統版面圖檔系統版面圖檔
  • 下載下載:0
  • 收藏至我的研究室書目清單書目收藏:0
本實驗我們將利用同步輻射光電子能譜來研究分析Ag/LiF/PFO及LiF/PFO介面處的電子結構。首先,我們發現當LiF沉積在PFO上時,LiF會分解而釋放出Li原子摻雜在PFO的表面,而此被摻雜的Li原子將會使得PFO表面處的電荷載子重新分佈,進而導致電子能譜中PFO的HOMO朝向高束縛能的方向移動,而使得靠近LiF的PFO表面處的能帶向下彎曲,降低電子注入的能障高度,增加電子從陰極注入有機層的機率,進而提升元件整體的效率。
然而,當在LiF/PFO表面漸漸沉積上一層銀之後,我們發現當被沉積在LiF/PFO表面處的銀很薄時,PFO的HOMO並無明顯的位移,其表示薄銀層的引入將不會導致能障高度有所改變,但卻會因其低電阻率的特性而幫助提升電子注入的效率;當所沉積的銀層逐漸增厚時,我們發現銀原子會提供電子給LiF/PFO,因此使得在費米能階附近產生一個新的電子能態,並導致PFO的HOMO慢慢的向低束縛能的方向移動,此現象告訴我們當被沉積的銀到達一定厚度之後,將會使得Ag/LiF/PFO介面處的電子注入能障提高,而使得沉積上愈厚銀的元件的光電特性逐漸降低,此結果與我們先前所做的元件之光電特性資料有相同的趨勢及現象。
Electronic structures of Ag/LiF/PFO and LiF/PFO interfaces are investigated by high-resolution synchrotron radiation photoemission spectroscopy. LiF is found to be decomposed and liberates Li ion to dope into PFO during depositing on PFO. The doped Li then releases electrons to make charges redistribution at the interface and realignment the energy levels by its low work function. This effect causes the HOMO of PFO to shift to high binding energy, resulting in the band bending at the near interface region of PFO, hence leading to the lowering of the electron injection barrier height as well as enhancing the electron injection efficiency from cathode to organic materials, bringing about the improvement of device performance. However, with increasing Ag deposition coverage onto LiF/PFO, it is shown that the onset position of HOMO shifts continuously toward low binding energy to be closer to Fermi-level. Because the deposited Ag layer will offer electrons to LiF/PFO, leading to the formation of negatively charged layer which can be considered as an accelerating electric field for photoelectrons, the shifts of HOMO to lower binding energy will come about. Therefore, it can be seen that the device with LiF/PFO deposited by thin Ag layer will not bring about electron injection barrier increase but will reduce resistivity. However, if the device is deposited with thick Ag layer, the effective barrier height of electron injection will be enhanced. The thicker Ag layer will offer electrons to LiF/PFO, leading to the formation of negatively charged layer, and then to shift the HOMO to low binding energy. This result will cause the reduction of device performance.
Chapter I Introduction…………………………...………………. 1
1-1 Motivation……………………………………….…….. 2
1-2 A brief history of organic light-emitting diodes…………. 4
1-3 The advantages of organic light-emitting diodes………… 6
1-4 The structures of OLED………………………………….. 7
1-5 The principle of OLED…………………………………… 9
1-6 The factors of effects on device performance…………… 11
Chapter II The aim of this study……………………….………….. 16
2-1 Arguments of literatures…………….…………………… 17
2-2 This aim of the study……………………...…………….. 20
2-3 Previous reports about interface reaction between silver and organic materials……………………………………. 22
Chapter III Experiment……….……….……………..…………. 27
3-1 Materials………………………………………………… 28
3-2 The establishing of devices……………………..……… 29
3-2-1 Experimental system and procedure……………… 29
3-2-2 Measure systems…………………………….…… 32
3-2-2-1 I-V-L measurement……………………… 32
3-2-2-2 Thickness measurement………………… 32
3-3 Interface analysis………………………………………... 34
3-3-1 Introduction of photoemission spectroscopy……… 34
3-3-2 Experimental system and procedures……………… 37
3-3-2-1 Synchrotron radiation……………………. 37
3-3-2-2 Specifications for Beamline LSGM……… 39
3-3-2-3 Ultra-high vacuum chamber……………… 40
3-3-2-4 Sample preparation and materials evaporation………………………………... 42
Chapter IV Results and conclusions……………….…….………. 55
4-1 Device with a LiF insulator………………………………. 56
4-2 LiF/PFO interface……………………………………….. 62
4-3 Device with an Ag/LiF bilayer cathode………………… 65
4-4 Ag/LiF/PFO interface……………………………………. 67
Chapter V Conclusions……..……….....…………………………. 83
References……..……………………………………………….……. 86
[1]C. W. Tang, S. A. Vanslyke, and C. H. Chen, J. Appl. Phys. 65, 3610 (1989).
[2]C. Adachi, T. Tsutsui, and S. Saito, Appl. Phys. Lett. 57, 531 (1990).
[3]H. Razafitrimo, K. T. Park, E. Ettedgui, Y. Gao, and B. R. Hsieh, Polym. Int. 36, 147 (1995).
[4]Y. Gao, K. T. Park, and B. R. Hsieh, J. Appl. Phys. 73, 7894 (1993).
[5]L. S. Hung, C. W. Tang, and M. G. Mason, Appl. Phys. Lett. 70, 152 (1997).
[6]Ho Won Choi, Soo Young Kim, Woong-Kwon Kim, and Jong-Lam Lee, Appl. Phys. Lett. 87, 082102 (2005).
[7]L. S. Hung, C. W. Tang, and M. G. Mason, Appl. Phys. Lett. 70, 152 (1997).
[8]G. Mason, C. W. Tang, L. S. Hung, P. Raychaudhuri, J. Madathil, D. J. Giesen, L. Yan, Q. T. Le, Y. Gao, S. T. Lee, L. S. Liao, L. F. Cheng, W. R. Salaneck, D. A. dos Santos, and J. L. Bredas, J. Appl. Phys. 89, 2756 (2001).
[9]L. S. Hung, R. Q. Zhang, P. He, and G. Mason, J. Phys. D 35, 103 (2002).
[10]H. Heil, J. Steiger, S. Karg, M. Gastel, H. Orther, and H. von Seggem, J. Appl. Phys. 89, 420 (2001).
[11]Pope M., Kaltmann, H. P. and Magnante, P., J. Chem. Phys. 38, 2042 (1963).
[12]W. Helfrich, and W. G. Schneider, Phys. Rev. Lett. 14, 229 (1965).
[13]C. W. Tang, and S. A. VanSlyke, Appl. Phys. Lett. 51, 913 (1987).
[14]J. H. Burroughes, D. D. C. Bradley, A, R. Brown, R. N. Marks, K. Mackly, R. H. Friend, P. L. Burn, and A. B. Homes, Nature, 347, 539 (1990).
[15]T. Wakimoto, S. Kawami, K. Nagayama, Y. Yonemoto, R. Murayama, J. Funaki, H. Sato, H. Nakada, and K. Imai, International Symposium on Inorganic and Organic Electroluminescence, Hamamatsu (1994).
[16] Y. Park, J. Lee, S. K. Lee, and D. Y. Kim, Appl. Phys. Lett. 79, 105 (2001).
[17]J. Lee, Y. Park, S. K. Lee, E.-J. Cho, D. Y. Kim, H. Y. Chu, H. Lee, L.-M. Do, and T. Zyung, Appl. Phys. Lett. 80, 3123 (2002).
[18]F. Li, H. Tang, J. Anderegg, and J. Shinar, Appl. Phys. Lett. 70, 1233 (1997).
[19]H. Tang, F. Li, and J. Shinar, Appl. Phys. Lett. 71, 2560 (1997).
[20]R. Schlaf, B. A. Parkinson, P. A. Lee, K. W. Nebesny, G. Jabbour, B. Kippelen, N. Peyghambarian, and N. R. Armstrong, J. Appl. Phys. 84, 6729 (1998).
[21]S. E. Shaheen, G. E. Jabbour, M. M. Morrell, Y. Kawabe, B. Kippelen, N. Peyghambarian, M.-F. Nabor, R. Schlaf, E. A. Mash, and N. R. Armstron, J. Appl. Phys. 84, 2324 (1998).
[22]T. Mori, H. Fujikawa, S. Tokito, and Y. Taga, Appl. Phys. Lett. 73, 2763 (1998).
[23]D. Grozea, A. Turak, X. D. Feng, Z. H. Lu, D. Johnson, and R. Wood, Appl. Phys. Lett. 81, 3173 (2002).
[24]J. M. Zhao, S. T. Zhang, X. J. Wang,Y. Q. Zhan, X. Z. Wang, G. Y. Zhong, Z. J. Wang, X. M. Ding, W. Huang, and X. Y. Hou, Appl. Phys. Lett. 84, 2913 (2004).
[25]Y. E. Kim, H. Park, and J. J. Kim, Appl. Phys. Lett. 69, 599 (1996).
[26]X. J. Wang, J. M. Zhao, Y. C. Zhou, X. Z. Wang, S. T. Zhang, Y. Q. Zhan, Z. Xu, H. J. Ding, G. Y. Zhong, H. Z. Shi, Z. H. Xiong, Y. Liu, Z. J. Wang, E. G. Obbard, X. M. Ding, W. Huang, and X. Y. Hou, J. Appl. Phys. 95, 3828 (2004).
[27]S. T. Zhang, X. M. Ding, J. M. Zhao, H. Z. Shi, J. He, Z. H. Xiong, H. J. Ding, E. G. Obbard, Y. Q. Zhan, W. Huang, and X. Y. Hou, Appl. Phys. Lett. 84, 425 (2004).
[28]Y. Q. Zhan, Z. H. Xiong, H. Z. Shi, S. T. Zhang, Z. Xu, G. Y. Zhong, J. He, J. M. Zhao, Z. J. Wang, E. Obbard, H. J. Ding, X. J. Wang, X. M. Ding, W. Huang, and X. Y. Hou, Appl. Phys. Lett. 83, 1656 (2003).
[29]Huajun Peng, Xiuling Zhu, Jiaxin Sun, Zhiliang Xie, Shuang Xie, Man Wong, and Hoi-Sing Kwok, Appl. Phys. Lett. 87, 173505 (2005).
[30]T. Schwieger , H. Peisert, and M. Knupfer, Chemical Physics Letters 384, 197 (2004).
[31]Mihaela Gorgoi ,and Dietrich R.T. Zahn, Applied Surface Science 252, 5453 (2006).
[32]T.U. Kampen, A. Das, S. Park, W. Hoyer, and D.R.T. Zahn, Applied Surface Science 234, 333–340 (2004).
[33]L.F. Cheng, L.M. Hung, X.M. Ding, Z.Q. Gao, C.S. Lee, and S.T. Lee, Displays 21, 51–54 (2000).
[34]K. Siegbahn, C. Nordling, A. Fahlman, R. Nordberg, K. Hamrin, J. Hedman, G. Johansson, T. Bergmark, S. E. Karlsson, I. Kindgren, and B. Lindberg, Nova Acta Regiae Societatis Scientiarum Upsaliensis, Vol. Ser. IV 20 (1967).
[35]K. Siegbahn, Science 217, 111 (1982).
[36]C. R. Brundle, Sur. Sci 48, 99 (1975).
[37]Hisao Ishii, Adv. Mater. 11, 605 (1999).
[38]S. J. Kang, D. S. Park, S. Y. Kim, C. N. Whang, K. Jeong, and S. Im, Appl. Phys. Lett. 81, 2581 (2002).
[39]Pongpun Piromreun, HwanSool Oh, Yulong Shen, George G. Malliaras, J. Campbell Scott and Phil J. Brock, Appl. Phys. Lett. 77, 2403 (2000).
[40]Quoc Toan Le, Li Yan, Yongli Gao , M. G. Mason, D. J. Giesen, and C. W. Tang, J. Appl. Phys. 87, 375 (2000).
[41]M. G. Mason, C. W. Tang, L.-S. Hung, P. Raychaudhuri, J. Madathil, D. J. Giesen, L. Yan, Q. T. Le, Y. Gao , S.-T. Lee, L. S. Liao, L. F. Cheng, W. R. Salaneck, D. A. dos Santos, and J. L. Brédas, J. Appl. Phys. 89, 2756 (2001).
[42]L S Hung, R Q Zhang, P He, and G Mason, J. Phys. D: Appl. Phys. 35, 103–107 (2002).
[43]Chih-I Wu, Guan-Ru Lee, and Tun-Wen Pi, Appl. Phys. Lett. 87, 212108 (2005).
[44]J. M. Zhao, S. T. Zhang, X. J. Wang, Y. Q. Zhan, X. Z. Wang, G. Y. Zhong, Z. J. Wang, X. M. Ding, W. Huang, and X. Y. Hou, Appl. Phys. Lett. 84, 2913 (2004).
[45]J. M. Zhao, Y. Q. Zhan, S. T. Zhang, X. J. Wang, Y. C. Zhou, Y. Wu, Z. J. Wang, X. M. Ding, and X. Y. Hou, Appl. Phys. Lett. 84, 5377 (2004).
[46]J. Lee, Y. Park, D. Y. Kim, H. Y. Chu, H. Lee, and L.-M. Do, Appl. Phys. Lett. 82, 173 (2003).
[47]Tzung-Fang Guo, Fuh-Shun Yang, Zen-Jay Tsai, Ten-Chin Wen, Sung-Nien Hsieh, Yaw-Shyan Fu, and Chia-Tin Chung, Appl. Phys. Lett. 88, 113501 (2006).
[48]Young-Eun Kim, Heuk Park, and Jang-Joo Kim, Appl. Phys. Lett. 69, 599 (1996).
[49]F. Li, H. Tang, J. Anderegg, and J. Shinar, Appl. Phys. Lett. 70, 1233 (1997).
[50]K. C. Liu, C. W. Teng, C. C. Lee, K. Y. Cheng, Y. H. Lu, W. T. Liu, C. C. Chen and L. C. Chen, Japanese Journal of Applied Physics 45, 3742 (2006).
[51]Kou-Chen Liu, Chao-Wen Teng1, Yen-Hsun Lu, Yao-Chou Tsai, and Shih-Hsien Chou, Japanese Journal of Applied Physics 46, 2704 (2007).
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top
系統版面圖檔 系統版面圖檔