臺灣博碩士論文加值系統

本研究之目的在開發高效率及高亮度之高分子電致發光材料，內容涵蓋：（1）側鏈上不同陰電性基團結構改質之聚對位苯基乙稀系高分子；（2）發綠光之環上烷氧苯環基取代之聚對位苯基乙稀系高分子；（3）發黃光之環上甲氧基取代與環上烷氧苯環基取代之聚對位苯基乙稀系共聚物等材料之合成與鑑定。利用光譜的分析、電化學法的量測、X-ray的鑑定、TOF的量測、雙載子及單一載子元件的電壓-電流之特性曲線分析等方法，來瞭解側鏈結構的差異對其高分子膜的結構、物性及其發光二極體元件效能的影響，以期能開發出高亮度及高效率之發光二極體元件。
(1)我們在PPV衍生物的長側鏈末端引入不同結構的陰電性基團naphthyl-substituted oxadiazole (NOXD), phenyl-substituted oxadiazole (POXD), t-butylphenyl-substituted oxadiazole (BOXD),及t-butylphenyl-substituted triazole (BTAZ)，並探討其結構上的效應。此類陰電性基團的引入會對共軛主鏈造成稀釋效應，而此效應受其結構影響很大，我們發現末端異丁基（t-butyl）基團的引入可降低陰電性基團的極性，同時提高其立體障礙，使其能有效的將分子鏈分隔開，並因而提高其固態膜的螢光效率。此外，經由單一載子元件的分析，我們發現此類陰電性基團的引入的確可提高其電子的通量，而其利用共聚調整集團含量的方式，使得此四種陰電性基團改質的PPV衍生物均可找到一最適共聚比，使其元件效能有效的提升。綜合其效應，我們發現BTAZ基團對載子的調節性最好，此基團的引入可大範圍的調整電子通量對電洞通量的比，使得原為電洞主宰的PPV衍生物可被調整成電子主宰的材料。隨著此基團含量的調整，電子及電洞通量可被調整到以高功函數金屬（鋁）當負極的元件的效能，能夠達到與低功函數金屬（鈣）當負極的元件的效能相當的程度。
(2)我們探討兩種發綠光的PPV衍生物，一為均聚物2-[3’-(3,7-
dimethyloctyloxy)phenylene]-p-phenylene-vinylene (m-DMOP-PPV，gm)另一為共聚物50 % by mole 2-[4’-(3,7-dimethyloctyloxy)phenylene]-p-
phenylene-vinylene 和50 % 2-[3’-(3,7-dimethyloctyloxy)phenylene]-p-
phenylene-vinylene (p-DMOP—co-m-DMOP-PPV，gc)的載子傳遞行為及其電致發光元件的效能。我們發現前者有比後者更規則的分子鏈排列，而此規則排列導致載子的傳遞速度大幅的提高，尤其是對電子而言，其傳遞速度提升到與電洞傳遞速度一樣。其電子與電洞傳遞速度的平衡可說是造成其元件高亮度 (100,000 cd/m2) 及高效率 (12 cd/A) 的主要因素。
(3)我們將上述烷氧苯基取代的綠光材料經由與短側鏈的共聚單體[(2,5-dimethoxy-p-phenylene)vinylene] (DMeOPV)共聚的方式來改質，使其成為局部主鏈更規則排列的黃光材料。經由其單一載子元件的電荷通量的量測，發現決定電荷總傳遞速率的決定因素為不同分子鏈間的電荷傳遞，而此傳遞受分子鏈的結構及型態影響很大。另外，我們發現局部規則排列可提升電子的傳遞速度及通量，因而可用來調整電子及電洞的通量，以達到改善元件效能的目的。其分別含有共聚單體(DMeOPV) 10 及 25 % 的黃光材料的最大亮度分別為 57000 (在 15 V/90 nm) 及 73000 (在 13 V/83 nm) cd/m2; 而其最大效率分別為15.5 (在7 V/90 nm) 及 11.9 cd/A (在5.5 V/83 nm)。

This study is for developing new polymeric electroluminescent materials with high efficiency and brightness. It contains synthesis and identification of (1) different electronegative moieties modified PPVs, (2) green-emitting alkoxyphenyl substituted PPVs, and (3) yellow-emitting copolymers of dimethyl- and alkoxyphenyl- substituted PPVs. We investigate the effect of different side chain structure on the structure and property of polymer films and the performance of its electroluminescent devices by use of various spectroscopies, electrochemical analysis, X-ray diffraction, TOF measurements, and applied voltage-current characteristic curves of double- and single- carriers devices in order to obtain a highly bright and efficient light emitting diodes.
(1) We introduce different structure electronegative moieties, naphthyl-substituted oxadiazole (NOXD), phenyl-substituted oxadiazole (POXD), t-butylphenyl-substituted oxadiazole (BOXD), and t-butylphenyl-substituted triazole (BTAZ), in the end of the long side chain of PPVs and investigate their structure effect. The introducing of such electronegative moieties results in a dilution effect on conjugation main chain. We find the end-caped t-butyl group can reduce the polar of the electronegative moiety and increase steric hinder, which separate molecular chian effectively and promote photoluminescent efficiency of the polymer films. In addition, we find the introducing of such electronegative moieties indeed promotes its electron flux and performance of its electroluminescent device. Through adjustment of electronegative moiety content by copolymerization, we can find a suitable content to obtain maximum device efficiency. In summary, we find the incorporation of BTAZ moiety allows a tuning of the ratio of electron flux to hole flux in a broad range such that the originally hole-dominated transport in PPVs can turn to electron-dominated transport. As proper content of BTAZ is incorporated, the electron and hole fluxes can be tuned to an equivalent level for improving the efficiency and brightness of the device with the high work function metal, aluminum, as the cathode to a level equivalent to that with the low work function metal, calcium.
(2) Charge transport behaviors and performances of electroluminescent devices of the two green-emitting poly(phenylene vinylene)s, the homopolymer of 2-[3’-(3,7-dimethyloctyloxy)phenylene]-
p-phenylene-vinylene (m-DMOP-PPV) and the copolymer of 50 % by mole 2-[4’-(3,7-dimethyloctyloxy)phenylene]-p-phenylene-vinylene and 50 % 2-[3’-(3,7-dimethyloctyloxy)phenylene]-p-phenylene-vinylene (p-DMOP—co-m-DMOP-PPV) are investigated. The former is found to have more ordered chain alignment than the latter. Such ordered alignment leads to significant increases of the mobilities of charge carriers, especially for that of electron, which is promoted to a level equivalent to that of hole. The balance of electron and hole mobility could be the reason for its high brightness (100,000 cd/m2) and efficiency (12 cd/A) of the EL device.
(3) We have synthesized the yellow light emitting polymers by modifying the green emission alkoxyphenyl-substituted Poly(phenylene vinylene)s (PPV) through copolymeration with the short side chain comonomer [(2,5-dimethoxy-p-phenylene)vinylene] (DMeOPV) to allow a more locally ordered main chain structure. Through the charge carrier flux measurements on single carrier devices, it is found that the limiting factor that determines the overall rate of charge transport is the inter-chain charge transport, which is greatly affected by chain structure and morphology. The local order can promote the electron mobility and flux, which allows an adjusting of the electron and hole carriers fluxes to some extent such that an improvement in the device performance can be made. The maximum brightness of the yellow light emitting polymers with 10 and 25 % of comonomer (DMeOPV) are 57000 (at 15 V/90 nm) and 73000 (at 13 V/83 nm) cd/m2; and the maximum luminous efficiencies are 15.5 (at 7 V/90 nm) and 11.9 cd/A (at 5.5 V/83 nm), respectively.

摘要(中文) I
摘要(英文) IV
目錄 VIII
圖目錄 XI
表目錄 XVIII
第一章 緒論 1
1-1 前言 1
1-2 共軛導電高分子之電子狀態 4
1-3 螢光理論 9
1-3-1 螢光的成因 9
1-3-2 影響螢光的因素 10
1-3-3 螢光的能量轉移 13
1-4 金屬半導體理論 14
1-4-1 界面接合 14
1-4-2 電流傳遞過程 15
1-5 本文目的 18
第二章 文獻回顧 19
2-1不同光色的高分子材料 19
2-1-1 PPV系高分子 19
2-1-2 PFO系高分子 25
2-1-3 PPP系高分子 26
2-1-4 PT系高分子 27
2-2高分子發光二極體的研究 28
2-2-1 電荷的注入/傳遞及平衡 31
2-2-1-1電荷注入/傳遞的機制 31
2-2-1-2電子的注入 33
2-2-1-3電洞的注入 36
2-2-1-4發光層載子的傳遞特性及改質 38
2-2-2 發光層的螢光效率 47
2-2-3 單一激發態/三重激發態 51
2-3 文獻分析 53
第三章 實驗內容 55
3-1 藥品 57
3-2 儀器設備 60
3-3 二極體的製作及量測 63
3-3-1元件的製作 63
3-3-2 二極體的測試 64
第四章 電子與電洞注入平衡的PPV衍生物高分子：電子傳遞基團的結構效應 66
4-1 前言 66
4-2 實驗部分 69
4-2-1 高分子的合成 69
4-2-2 共聚物組成的鑑定 85
4-2-3 共軛主鏈上的缺陷 88
4-2-4 UV-Vis 光譜分析 91
4-2-5 PL光譜分析 97
4-2-6 X-ray繞射分析 103
4-2-7 PL量子效率的量測 104
4-2-8 循環伏安分析 107
4-2-9 元件的製作 109
4-2-10 發光二極體元件 111
4-2-11 單一載子元件 124
4-2-12 安定性分析 131
4-3 結果與討論 135
4-3-1 側鏈末端陰電性基團造成的稀釋效應 135
4-3-2 側鏈末端陰電性基團結構差異對氧化還原電位的影響 139
4-3-3 側鏈末端陰電性基團結構差異對元件效能及載子平衡的影響 140
4-3-4 側鏈末端陰電性基團對載子移動速度及數目的全範圍調整 144
4-4 結論及重要性 161
第五章 綠光PPV衍生物的結構排列對其電荷載子傳遞速度的效應 162
5-1 前言 162
5-2 實驗部分 164
5-2-1 高分子的合成 164
5-2-2 共軛主鏈上的缺陷 174
5-2-3 分子量分佈 176
5-2-4 X-ray繞射分析 178
5-2-5 UV-Vis及PL光譜分析 180
5-2-6 元件的製作 187
5-2-7 EL光譜分析 188
5-2-8 發光二極體元件 189
5-2-9 循環伏安分析 190
5-2-10 單一載子元件 193
5-2-11 Time-of-Flight 的量測 196
5-3 結果與討論 197
5-4 結論 205
第六章 高效率高分子（PPVs）發光二極體：電子與電洞通量的平衡 206
6-1 前言 206
6-2 實驗部分 208
6-2-1 高分子的合成 208
6-2-2 共聚物組成的鑑定 210
6-2-3 共軛主鏈上的缺陷 212
6-2-4 分子量分佈 213
6-2-5 X-ray繞射分析 214
6-2-6 元件的製作 215
6-2-7 發光二極體元件 216
6-2-8 單一載子元件 220
6-3 結果與討論 222
6-4結論 233
第七章 總結與未來展望 234
本研究之原創性工作 237
參考文獻 238
自傳 252
著作目錄 253
圖 目 錄
Figure 1-1-1. The structure and abbreviation of conjugated polymers.-------------------1
Figure 1-1-2. Comparison of electrical conductivities of metals, semiconductors and insulators; d indicates the doped material.---------------------------------3
Figure 1-2-1. Band structure of semiconductor. IP: ionization potential, EA:electron affinity, EF: Femi level, E D: donor level, EA: acceptor level.-----------7
Figure 1-2-2. The representation of the energy levels of MOs with increasing size of the molecule for [CH]n.--------------------------------------------------------8
Figure 1-2-3. The energy levels of polaron and bipolaron.---------------------------------8
Figure 1-3-1. The formation of fluorescence and phosphorescence of molecules.----12
Figure 1-4-1. Barriers for semiconductors of different types and work functions. n-type: (a) Φm > Φs (Schottky) ; (b) Φm < Φs (Ohmic). p-type : (c) Φm < Φs (Schottky); (d) Φm > Φs (Ohmic).------------------------------------17
Figure 1-4-2. Transport processes in a forward-biased Schottky barriers.--------------17
Figure 2-2-1. Schematic structure of polymer LED and carrier transport in LED.----29
Figure 2-2-2. Band diagram of singlet exciton formation in (a) PL and (b) EL processes.----------------------------------------------------------------------30
Figure 2-2-3. Schematic structure of ITO/PPV/PBD:PMMA/Ca and carrier transport in this device.------------------------------------------------------------------35
Figure 2-2-4. Correlation diagram between the photoluminescence quantum efficiency and the conjugational dimension of lumophores.------------48
Figure 2-2-5. The σS/σT ratio for several π-conjugated polymers and oligomers as a function of the optical gap, Eg.--------------------------------------------52
Figure 4-2-1. Synthetic Route for NOXD and POXD (OXD) moieties modified PPVs.---------------------------------------------------------------------------69
Figure 4-2-2. Synthetic Route for BOXD moiety modified PPVs.----------------------70
Figure 4-2-3. Synthetic Route for BTAZ moiety modified PPVs.-----------------------71
Figure 4-2-4. UV-Vis spectra of (a) CHCl3 (mg/L) solution and (b) thin solid films on quartz of MEH-PPV (7), MTPD-PPV (T100), and their statistical copolymers (T25-T80).------------------------------------------------------94
Figure 4-2-5. UV-Vis spectra of thin solid films of MEH-PPV (7), BOPD-PPV (B100), and their statistical copolymers (B30-B80).------------------------------95
Figure 4-2-6. UV-Vis spectra of thin solid films of MEH-PPV (7), NOPD-PPV (N100), and their statistical copolymers (N20-N85).--------------------95
Figure 4-2-7. UV-Vis spectra of thin solid films of NOPD-PPV (N100), BOPD-PPV (B100), and MTPD-PPV (T100).-------------------------------------------96
Figure 4-2-8. The absorption maximums of CHCl3 solution and thin solid films of NOPD-PPVs (N20-N100), BOPD-PPVs (B30-B100), and MTPD-PPVs (T25-T100) related to absorption maximums of MEH-PPV (7).----------------------------------------------------------------96
Figure 4-2-9. PL spectra of (a) CHCl3 (mg/L) solution and (b) thin solid films on quartz of MEH-PPV (7), MTPD-PPV (T100), and their statistical copolymers (T25-T80).------------------------------------------------------99
Figure 4-2-10. PL spectra of thin solid films of MEH-PPV (7), BOPD-PPV (B100), and their statistical copolymers (B30-B80).-----------------------------100
Figure 4-2-11. PL spectra of thin solid films of MEH-PPV (7), NOPD-PPV (N100), and their statistical copolymers (N20-N85).-----------------------------100
Figure 4-2-12. Photoluminescent spectra of NOPD-PPV (N100) film and solutions at various concentrations (mole of their repeat units/L) excitated at the wavelengths of their main chain absorption maxima.------------------101
Figure 4-2-13. Photoluminescent spectra of BOPD-PPV (B100) film and solutions at various concentrations (mole of their repeat units/L) excitated at the wavelengths of their main chain absorption maxima.------------------101
Figure 4-2-14. Photoluminescent spectra of MTPD-PPV (T100) film and solutions at various concentrations (mole of their repeat units/L) excitated at the wavelengths of their main chain absorption maxima.------------------102
Figure 4-2-15. Photoluminescent spectra of MEH-PPV film and solutions at various concentrations (mole of their repeat units/L) excitated at the wavelengths of their main chain absorption maxima.------------------102
Figure 4-2-16. Wide-angle X-ray diffraction patterns of polymers MEH-PPV (7), MTPD-PPV (T100), and their statistical copolymers (T25-T80).---103
Figure 4-2-17. (a) PL spectra and (b) UV-Vis spectra of thin solid films on quartz of MEH-PPV (7), MTPD-PPV (T100), and their statistical copolymers (T25-T80).-------------------------------------------------------------------105
Figure 4-2-18. PLE spectra of thin solid films on quartz of MEH-PPV (7), MTPD-PPV (T100), and their statistical copolymers (T25-T80).---106
Figure 4-2-19. Cyclic voltammogram of ferrocene/ferrocenium in 0.1 M n-Bu4NClO4 in dry PC with scan rate of 100 mV/s.-----------------------------------108
Figure 4-2-20. Cyclic voltammogram of NOPD-PV, BOPD-PV, and MTPD-PV in 0.5 M Bu4NClO4 in pentanenitrile with scan rate of 100 mV/s.----------108
Figure 4-2-21. Current density-electric field characteristics for the devices with the NOPD-MEH-PPV derivatives: (a) ITO/polymer/Ca/Al, (b) ITO/polymer/Al. The devices are fabricated by procedure 1.---------114
Figure 4-2-22. Brightness-electric field characteristics for the devices with the NOPD-MEH-PPV derivatives: (a) ITO/polymer/Ca/Al, (b) ITO/polymer/Al. The devices are fabricated by procedure 1.---------115
Figure 4-2-23. Efficiency-current density characteristics for the devices with the NOPD-MEH-PPV derivatives: (a) ITO/polymer/Ca/Al, (b) ITO/polymer/Al. The devices are fabricated by procedure 1.---------116
Figure 4-2-24. Current density-electric field characteristics for the devices with the BOPD-MEH-PPV derivatives: (a) ITO/polymer/Ca/Al, (b) ITO/polymer/Al. The devices are fabricated by procedure 1.---------117
Figure 4-2-25. Brightness-electric field characteristics for the devices with the BOPD-MEH-PPV derivatives: (a) ITO/polymer/Ca/Al, (b) ITO/polymer/Al. The devices are fabricated by procedure 1.---------118
Figure 4-2-26. Efficiency-current density characteristics for the devices with the BOPD-MEH-PPV derivatives: (a) ITO/polymer/Ca/Al, (b) ITO/polymer/Al. The devices are fabricated by procedure 1.---------119
Figure 4-2-27. Current density-electric field characteristics for the devices with the MTPD-MEH-PPV derivatives: (a) ITO/polymer/Ca/Al, (b) ITO/polymer/Al. The devices are fabricated by procedure 1.---------120
Figure 4-2-28. Brightness-applied voltage characteristics for the devices with the MTPD-MEH-PPV derivatives: (a) ITO/polymer/Ca/Al, (b) ITO/polymer/Al. The devices are fabricated by procedure 1.---------121
Figure 4-2-29. Current density-electric field characteristics for the devices with the MTPD-MEH-PPV derivatives: (a) ITO/PEDOT/polymer/Ca/Al, (b) ITO/PEDOT/polymer/Al. The devices are fabricated by procedure 2.-------------------------------------------------------------------------------122
Figure 4-2-30. Current density-electric field characteristics for the devices with the MTPD-MEH-PPV derivatives: (a) ITO/PEDOT/polymer/Ca/Al, (b) ITO/PEDOT/polymer/Al. The devices are fabricated by procedure 2.-------------------------------------------------------------------------------123
Figure 4-2-31. Current density versus electrical field for the devices: (a) ITO/polymer/Au [hole-dominated] and (b) Ca/polymer/Ca [electron-dominated]. The devices are fabricated by procedure 2.---127
Figure 4-2-32. Plots according to the space-charge-limited current model for the electron (open symbols)- and hole(closed symbols)-dominated PPV-derivatives-based devices. The lines are fits to space-charge-limited behavior.--------------------------------------------128
Figure 4-2-33. Mobility versus electrical field for the electron (open symbols)- and hole (closed symbols)-dominated devices.------------------------------128
Figure 4-2-34. (a) hole and (b) electron carrier densities for space-charge-limited current of the hole- and electron-dominated PPV-derivatives-based devices.-----------------------------------------------------------------------129
Figure 4-2-35. PL spectra of thin solid films on quartz of MEH-PPV (7), MTPD-PPV (T100), and their statistical copolymers (T25-T80).-------------------132
Figure 4-2-36. Electroluminescence spectra of the devices (a) ITO/polymer/Al and (b) ITO/polymer/Ca/Al with polymers 7, T40, T60, T80, and T100.----133
Figure 4-3-1. Photoluminescent spectra of NOPD-PPV (N100), POPD-PPV (P100), BOPD-PPV (B100), and MTPD-PPV (T100) film and solutions at various concentrations (mole of their repeat units/L) excitated at the wavelengths of their main chain absorption maxima.------------------151
Figure 4-3-2. Electroluminescent spectra of NOPD-PPV (N100), POPD-PPV (P100), BOPD-PPV (B100), and MTPD-PPV (T100).--------------------------152
Figure 4-3-3. Overlaid chromatogram of GPC for polymers 7, T40, T60, T80, and T100.--------------------------------------------------------------153
Figure 4-3-4. Cyclic voltammograms of MEH-PPV (7), MTPD-PPV (T100), and MTPD-MEH-PPVs (T25-T80) on ITO substrate (a) in 0.1 M Bu4NClO4 in dry propylene carbonate, (b) in 0.5 M in Bu4NClO4 pentanenitrile.---------------------------------------------------------------154
Figure 4-3-5. Band diagram of MTPD-PPV (T100), MTPD-MEH-PPVs (T25-T80), MEH-PPV (7), BTAZ, BOXD, and NOXD with the work functions of ITO, Al, and Ca.------------------------------------------------------------155
Figure 4-3-6. Maximum brightness (a) and efficiency (b) of the devices with Ca as the cathode for the polymers of various extent of BOXD (■), POXD (●), NOXD (▲), and BTAZ (▼) moieties modified PPVs. The devices are fabricated by procedure 1.------------------------------------------------156
Figure 4-3-7. Maximum brightness (a) and efficiency (b) of the devices with Al as the cathode for the polymers of various extent of BOXD (■), POXD (●), NOXD (▲), and BTAZ (▼) moieties modified PPVs. The devices are fabricated by procedure 1.------------------------------------------------157
Figure 4-3-8. Current density-electrical field and brightness-current density (inset) characteristics for the devices with the MTPD-MEH-PPV derivatives: (a) ITO/PEDOT/polymer/Ca/Al, (b) ITO/PEDOT/polymer/Al. The devices are fabricated by procedure 2.----------------------------------158
Figure 4-3-9. Current density versus electrical field for the devices ITO/polymer/Au [hole-dominated] and Ca/polymer/Ca [electron-dominated (inset)]. The devices are fabricated by procedure 2.----------------------------------159
Figure 4-3-10. Mobility versus electrical field for the electron (open symbols)- and hole (closed symbols)-dominated devices.-----------------------------160
Figure 5-2-1. Synthetic Route for monomer 7.------------------------------------------164
Figure 5-2-2. Synthetic Route for monomer 12.------------------------------------------165
Figure 5-2-3. Synthetic Route for polymers gm, gc, and gp.---------------------------166
Figure 5-2-4. Overlaid chromatograms of GPC for polymers gc, gm, and gp.-------177
Figure 5-2-5. Wide-angle X-ray diffraction patterns of polymers used.---------------179
Figure 5-2-6. UV-Vis spectra of (a) CHCl3 (mg/L) solution and (b) thin solid films spin-coated from its CHCl3 solutions (7 mg/ml) of the polymers used.---------------------------------------------------------------------------182
Figure 5-2-7. PL spectra of (a) CHCl3 (mg/L) solution and (b) thin solid films spin-coated from its CHCl3 solutions (7 mg/ml) of the polymers used.---------------------------------------------------------------------------183
Figure 5-2-8. PL spectra of thin films treated with thermal annealing for (a) 2 hours and (b) 6 hours.--------------------------------------------------------------184
Figure 5-2-9. UV-Vis spectra of thin films treated with thermal annealing for 6 hours.-------------------------------------------------------------------------185
Figure 5-2-10. (a) UV-Vis and (b) PL spectra of thin solid films spin-coated from its toluene solutions (5 mg/ml) of the polymers used.---------------------186
Figure 5-2-11. Electroluminescence spectra of the devices ITO/PEDOT/polymer/Ca/Al with polymers gc and gm.--------------188
Figure 5-2-12. Current density-electric field, brightness-electric field, and efficiency-electric field (inset) characteristics for the devices of polymers gc and gm.-------------------------------------------------------189
Figure 5-2-13. Cyclic voltammograms of the PPV derivatives on ITO substrate (a) in 0.5 M Bu4NClO4 in pentanenitrile, (b) in 0.1 M Bu4NClO4 in pentanenitrile at a sweep rate of 100 mV/s versus ferrocene/ferrocennium system (Ag/Ag+ as the reference electrode).--------------------------------------------------------------------191
Figure 5-2-14. Band diagram of polymers gc and gm with the work functions of ITO, PEDOT-PSS, and Ca.-------------------------------------------------------192
Figure 5-2-15. Current density versus electrical field for the devices ITO/PEDOT/polymer/Au [hole-dominated] and Al/polymer/Ca [electron-dominated] of polymers gc and gm.--------------------------194
Figure 5-2-16. Plot was electron-dominated and hole-dominated curves plotted in the format ln(JL3/V2) vs (VL)0.5, where J is the current density, L the polymer thickness, V the applied voltage decreased of the built-in potential, and the built-in potential = 1.4 eV.----------------------------195
Figure 5-3-1. Chemical structures and wide-angle X-ray diffraction patterns of polymers gc and gm.--------------------------------------------------------201
Figure 5-3-2. Time-of-flight transients of (a) hole, (b) electron for polymer gm of the same sample, and (c) hole for polymer gc after excitation through ITO anode with light pulses of 430 nm at room temperature. The films thickness were 1.2 μm for polymer gm and 1.5 μm for polymer gc, and the measurement was performed with an applied field of (a) 7.1×105, (b) 9.2×105, and (c) 7.2×105 V/cm, respectively. The inset shows the data replotted on log-log axes. The transit time tT is indicated by an arrow.-------------------------------------------------------------------------202
Figure 5-3-3. Current density versus electrical field for the devices ITO/PEDOT/polymer/Au [hole-dominated] and Al/polymer/Ca [electron-dominated] of polymers gc and gm. The inset was electron-dominated curves plotted in the format ln[JL3/(Vappl-Vbi)2] vs [(Vappl-Vbi)L]0.5, where J is the current density, L the polymer thickness, Vappl the applied voltage, Vbi the built-in potential taking as 1.4 eV.-203
Figure 5-3-4. Hole and electron mobilities determined from time-of-flight measurement and calculated by applying the space-charge-limited current model on J-V characteristics of polymers gm and gc.--------204
Figure 6-2-1. Synthesis Route of PPVs.---------------------------------------------------208
Figure 6-2-2. Overlaid chromatograms of GPC for polymers y10, y25, gc, and gm.----------------------------------------------------------------------------213
Figure 6-2-3. Wide-angle X-ray diffraction patterns of polymers used.---------------214
Figure 6-2-4. Current density-applied voltage-brightness and efficiency- applied voltage (inset) characteristic curves for the devices ITO/PEDOT/polymer/Ca/Al with polymers y10 (a) and y25 (b).----217
Figure 6-2-5. (a) Current density - electrical field and (b) brightness - electrical field characteristic curves for the devices ITO/PEDOT/polymer/Ca/Al with polymers gc, gm, y10, and y25.-------------------------------------------218
Figure 6-2-6. Efficiency - electrical field characteristic curves for the devices ITO/PEDOT/polymer/Ca/Al with polymers gc, gm, y10, and y25.--219
Figure 6-2-7. Current density-electrical field for the single carrier devices ITO/polymer/Au [hole-dominated] and Al/polymer/Ca [electron-dominated].-------------------------------------------------------221
Figure 6-3-1. Absorption and photoluminescence spectra of thin films of polymers gc, y10, and y25.-----------------------------------------------------------------228
Figure 6-3-2. Electroluminescence spectra (at about 100 cd/m2) of the devices ITO/PEDOT/polymer/Ca/Al with polymers gc, y10, and y25.-------229
Figure 6-3-3. Current density-electric field-brightness and efficiency-electric field (inset) characteristic curves for the devices ITO/PEDOT/polymer/Ca/Al with polymers gc, y10, and y25.-------230
Figure 6-3-4. Current density-electrical field for the single carrier devices ITO/polymer/Au [hole-dominated] and Ca/polymer/Ca [electron-dominated].-------------------------------------------------------231
Figure 6-3-5. Wide-angle X-ray diffraction patterns of polymers gc, y10, and y25.-232
表 目 錄
Table 1-3-1. The influence of the different substituents on fluorescence.--------------12
Table 4-2-1. Elemental analysis (EA) results and the theoretic values of MEH-PPV and MTPD-PPVs.---------------------------------------------------------------87
Table 4-2-2. Conjugational defects of MEH-PPV and MTPD-PPVs.-------------------90
Table 4-2-3. The zero-field mobilityμ0, zero-field E0, mobilityμ, and carrier densities for space-charge-limited current of the electron- and hole-dominated PPV-derivatives-based devices.---------------------------------------------130
Table 4-2-4. PL and EL λmax of polymers 7, T40, T60, T80, T100.-----------------134
Table 4-3-1. Molecular weightsa of the polymers MEH-PPV (7) and BTAZ moieties modified PPVs.----------------------------------------------------------------149
Table 4-3-2. Devices characteristics of polymers MEH-PPV (7) and BTAZ moieties modified PPVs. The devices are fabricated by procedure 2.------------150
Table 5-2-1. Conjugational defects of polymers gm, gc, and gp.----------------------175
Table 5-2-2. Molecular weights of polymers gm, gc, and gp.--------------------------177
Table 6-2-1. Elemental analysis (EA) results and the theoretic values of polymers gc, y10, and y25.-------------------------------------------------------------------211
Table 6-2-2. Conjugational defects of polymers gc, gm, y10, and y25.---------------212
Table 6-3-1. Characteristic Properties of the PPVs Synthesized.-----------------------226
Table 6-3-2. Device Characteristic Results of the PPVs.--------------------------------227

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