臺灣博碩士論文加值系統

我們利用ITO/NBP (50 nm)/LT-N421:C6 (0.4 wt%, 32 nm)/ DPVBi (8 nm)/ Alq3 (20 nm)/LiF (1 nm)/Al (200 nm)結構成功地製作出一高效率與亮度的藍綠光有機發光二極體。將DPVBi層加入於發光層和電子傳輸層之間時，於再結合區能獲得一較好的電荷平衡與提升元件的性能。DPVBi不僅被作為藍色發光層更能幫助電子從Alq3注入至LT-N421中，以及避免電洞進入到電子傳輸層。LT-N421是一新藍光主體材料而Coumarin6 (C6)則是一綠光客體材料，將兩者共掺雜來獲得藍綠光。C6最佳的摻雜濃度為0.4 wt%且能有最佳的能量轉換。由於是單一發光層，因此元件色光非常穩定。當外加11 V電壓時，元件色座標為x = 0.22, y = 0.43而最高亮度為42400 cd/m2，最高電流與功率效率在11 V與6 V分別為8.83 cd/A和3.96 lm/W。

A high efficiency and luminance of blue-green organic light-emitting diode (BGOLED) was successfully fabricated using the structure of ITO/NBP (50 nm)/LT-N421:C6 (0.4 wt%, 32 nm)/DPVBi (8 nm)/ Alq3 (20 nm)/LiF (1 nm)/Al (200 nm). Adding a DPVBi layer between the emission layer (EML) and electron transporting layer (ETL), a better charge balance in the recombination zone and a improved a performance could be obtained. DPVBi is not only used as the blue emission layer but also helps electrons injection into the LT-N421 layer from the Alq3 and avoids holes injection into the electron transporting layer. LT-N421 was a new blue emission host material and Coumarin 6 (C6) was a green emission dye as the guest material, we doped C6 into the LT-N421 layer to obtain blue-green emission. We found the optimum doping concentration was 0.4 wt% of C6 doped in LT-N421 layer and had the best energy transfer from LT-N421 to C6. The blue-green emission was stable because it was a single emission layer structure. The CIE coordinates of the device were x = 0.22, y = 0.43 when the maximum luminance was 42400 cd/m2 at 11 V. The maximum current efficiency and power efficiency were 8.83 cd/A at 11 V and 3.96 lm/W at 6 V, respectively.

Content

Abstract (in Chinese) I
Abstract (in English) II
Acknowledgement IV
Content V
Table Captions VII
Figure Captions VIII
Chapter 1 1
Introduction 1
1-1 The history of display 1
1-2 The outset of OLEDs 2
1-3 The advantages of OLEDs 4
Chapter 2 Review of publications 5
2-1 Material of OLEDs 5
2-1-1 Material of cathode 5
2-1-2 Material of anode 6
2-1-3 Hole injecting material (HIM) 7
2-1-4 Hole transporting material (HTM) 8
2-1-5 Electron injecting material (EIM) 8
2-1-6 Electron transporting material (ETM) 9
2-2 The operation theory of OLEDs 10
2-2-1 Absorption and emission 10
2-2-2 Energy transfer 10
2-2-3 Efficiency calculation 11
Chapter 3 Experiments and measurement system configuration 13
3-1 Materials 13
3-2 The treatment of substrate 14
3-3 Deposition system 15
3-4 Deposition of organic and metal thin films 17
3-5 Measurements 18
Chapter 4 Results and discussion 19
4-1 ITO/NPB (50 nm)/LT-N421 (40 nm)/Alq3 (x nm)/Al (200 nm) 19
4-2 ITO/NPB (60 nm)/LT-N421 (40 nm)/Alq3 (x nm)/Al (200 nm) 22
4-3 ITO/NPB (50 nm)/LT-N421 (40 - x nm)/DPVBi (x nm)/Alq3 (20 nm) /Al (200 nm) 25
4-4 ITO/NPB (50 nm)/ DPVBi (x nm)/LT-N421 (40 - x nm)/Alq3 (20 nm) /Al (200 nm) 28
4-5 ITO/NPB (50 nm)/ DPVBi (x nm)/LT-N421 (32 nm)/DPVBi (8 – x nm)/Alq3 (20 nm) /Al (200 nm) 30
4-6 ITO/NPB (50 nm)/LT-N421 (40 nm)/LiF (x nm)/Alq3 (x nm)/Al (200 nm) 33
4-7 ITO/NBP (50 nm)/DPVBi (x nm)/LT-N421 (32 nm)/DPVBi (8-x nm)/LiF (1 nm)/Alq3 (20 nm)/Al (200 nm) 35
4-8 ITO/NBP (50 nm)/LT-N421:C6 (x wt%, 40 nm)/Alq3 (20 nm)/Al (200 nm) 37
4-9 ITO/NBP (50 nm)/LT-N421:C6 (x wt%, 40 nm)/Alq3 (20 nm)/Al (200 nm) 40
4-10 ITO/NBP (50 nm)/LT-N421:C6 (x wt%, 40 nm)/Alq3 (20 nm)/ LiF (1 nm)/Al(200 nm) 42
4-11 ITO/NBP (50 nm)/LT-N421:C6 (x wt% 32 nm)/DPVBi (8 nm)/ Alq3 (20 nm)/LiF (1 nm)/Al (200 nm) 44
4-12 ITO/NBP(50 nm)/LT-N421:C6(0.1 wt%, 40 nm)/LiF (1 nm)/Alq3(20 nm)/LiF (1 nm)/Al(200 nm) 46
4-13 ITO/NBP (50 nm)/DPVBi (2 nm)/LT-N421:C6 (0.1 wt%, 32 nm)/ DPVBi (6 nm)/ LiF (1 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm) 48
Chapter 5 Conclusion 51
References 53
Publication list 61

Table Captions

Chapter 1
Table1- 1 The properties comparison between the flat panel displays (FPDs). 62

Figure Captions

Chapter 1

Fig. 1- 1 The comparison of inorganic LED and organic LED in the development of luminescence efficiency. 63

Chapter 2

Fig. 2 - 1 The processes of luminescence. 644
Fig. 2 - 2 The mechanism of radiative energy transfer. 655
Fig. 2 - 3 The mechanism of nonradiative energy transfer (a) Förster transfer by resonant dipole-dipole coupling, and (b) Dexter transfer by electron exchange. 655

Chapter 3

Fig. 3 - 1 Chemical structures of NPB, LT-N421, Coumarin 6, DPVBi and Alq3. 666
Fig. 3 - 2 Thermal vacuum evaporation system. 677

Chapter 4

Fig. 4 - 1 (a) The basic structure of devices (1) ~ (3). (b) The energy-level diagram of devices (1) ~ (3). 68
Fig. 4 - 2 The luminance-voltage curves of devices (1) ~ (3). 69
Fig. 4 - 3 The current-voltage curves of devices (1) ~ (3). 69
Fig. 4 - 4 The current efficiency-voltage curves of devices (1) ~ (3). 70
Fig. 4 - 5 The EL spectra of devices (1) ~ (3) at 10 V. 70
Fig. 4 - 6 The CIE coordinates of devices (1) ~ (3) at different voltages. 71
Fig. 4 - 7 The luminance-voltage curves of devices (4) ~ (6). 72
Fig. 4 - 8 The current-voltage curves of devices (4) ~ (6). 72
Fig. 4 - 9 The current efficiency-voltage curves of devices (1) ~ (3). 73
Fig. 4 - 10 The EL spectra of devices (4) ~ (6) at 10 V. 73
Fig. 4 - 11 The CIE coordinates of device (4) ~ (6) at different voltages. 74
Fig. 4 - 12 (a) The basic structure of devices (7) ~ (9). (b) The energy-level diagram of devices (7) ~ (9). 75
Fig. 4 - 13 The luminance-voltage curves of devices (7) ~ (9). 76
Fig. 4 - 14 The current-voltage curves of devices (7) ~ (9). 76
Fig. 4 - 15 The current efficiency-voltage curves of devices (7) ~ (9). 77
Fig. 4 - 16 The EL spectra of devices (7) ~ (9) at 10 V. 77
Fig. 4 - 17 The CIE coordinates of devices (7) ~ (9) at different voltages. 78
Fig. 4 - 18 (a) The basic structure of devices (10) ~ (12). (b) The energy- level diagram of devices (10) ~ (12). 79
Fig. 4 - 19 The luminance-voltage curves of devices (10) ~ (12). 80
Fig. 4 - 20 The current-voltage curves of devices (10) ~ (12). 80
Fig. 4 - 21 The current efficiency-voltage curves of devices (10) ~ (12). 81
Fig. 4 - 22 The EL spectra of devices (10) ~ (12) at 10 V. 81
Fig. 4 - 23 the CIE coordinates of devices (10) ~ (12) at different voltages. 82
Fig. 4 - 24 (a) The basic structure of devices (13) ~ (15). (b) The energy- level diagram of devices (13) ~ (15). 83
Fig. 4 - 25 The luminance-voltage curves of devices (13) ~ (15). 84
Fig. 4 - 26 The current-voltage curves of devices (13) ~ (15). 84
Fig. 4 - 27 The current efficiency-voltage curves of devices (13) ~ (15). 85
Fig. 4 - 28 The EL spectra of devices (13) ~ (15) at 10 V. 85
Fig. 4 - 29 The CIE coordinates of devices (13) ~ (15) at different voltages. 86
Fig. 4 - 30 (a) The basic structure of devices (16) ~ (18). (b) The energy- level diagram of devices (16) ~ (18). 87
Fig. 4 - 31 The luminance-voltage curves of devices (16) ~ (18). 88
Fig. 4 - 32 The current-voltage curves of devices (16) ~ (18). 88
Fig. 4 - 33 The current efficiency-voltage curves of devices (16) ~ (18). 89
Fig. 4 - 34 The EL spectra of devices (16) ~ (18) at 10 V. 89
Fig. 4 - 35 The CIE coordinates of devices (16) ~ (18) at different voltages. 90
Fig. 4 - 36 (a) The basic structure of devices (19) ~ (21). (b) The energy- level diagram of devices (19) ~ (21). 91
Fig. 4 - 37 The luminance-voltage curves of devices (19) ~ (21). 92
Fig. 4 - 38 The current-voltage curves of devices (19) ~ (21). 92
Fig. 4 - 39 The current efficiency-voltage curves of devices (19) ~ (21). 93
Fig. 4 - 40 The EL spectra of devices (19) ~ (21) at 10 V. 93
Fig. 4 - 41 The CIE coordinates of devices (19) ~ (21) at different voltages. 94
Fig. 4 - 42 (a) The basic structure of devices (22) ~ (24). (b) The energy- level diagram of devices (22) ~ (24). 95
Fig. 4 - 43 The luminance-voltage curves of devices (22) ~ (24). 96
Fig. 4 - 44 The current-voltage curves of devices (22) ~ (24). 96
Fig. 4 - 45 The current efficiency-voltage curves of devices (22) ~ (24). 97
Fig. 4 - 46 The EL spectra of devices (22) ~ (24) at 10 V. 97
Fig. 4 - 47 The CIE coordinates of devices (22) ~ (24) at different voltages. 98
Fig. 4 - 48 The luminance-voltage curves of devices (25) ~ (27). 99
Fig. 4 - 49 The current-voltage curves of devices (25) ~(27). 99
Fig. 4 - 50 The current efficiency-voltage curves of devices (25) ~ (27). 100
Fig. 4 - 51 The EL spectra of devices (25) ~ (27) at 10 V. 100
Fig. 4 - 52 The CIE coordinates of devices (25) ~ (27) at different voltages. 101
Fig. 4 - 53 (a) The basic structure of devices (28) ~ (30). (b) The energy- level diagram of devices (28) ~ (30). 102
Fig. 4 - 54 The luminance-voltage curves of devices (28) ~ (30). 103
Fig. 4 - 55 The current-voltage curves of devices (28) ~ (30). 103
Fig. 4 - 56 The current efficiency-voltage curves of devices (28) ~ (30). 104
Fig. 4 - 57 The EL spectra of devices (28) ~ (30) at 10 V. 104
Fig. 4 - 58 The CIE coordinates of devices (28) ~ (30) at different voltages. 105
Fig. 4 - 59 (a) The basic structure of devices (31) ~ (33). (b) The energy- level diagram of devices (31) ~ (33). 106
Fig. 4 - 60 The luminance-voltage curves of devices (31) ~ (33). 107
Fig. 4 - 61 The current-voltage curves of devices (31) ~ (33). 107
Fig. 4 - 62 The current efficiency-voltage curves of devices (31) ~ (33). 108
Fig. 4 - 63 The EL spectra of devices (28) ~ (30) at 10 V. 108
Fig. 4 - 64 The CIE coordinates of devices (31) ~ (33) at different voltages. 109
Fig. 4 - 65 (a) The basic structure of devices (34). (b) The energy- level diagram of devices (34). 110
Fig. 4 - 66 The luminance-voltage curves of devices (28) and (34). 111
Fig. 4 - 67 The current-voltage curves of devices (28) and (34). 111
Fig. 4 - 68 The current efficiency-voltage curves of devices (28) and (34). 112
Fig. 4 - 69 The EL spectra of devices (28) and (34) at 10 V. 112
Fig. 4 - 70 The CIE coordinates of device (34) at different voltages. 113
Fig. 4 - 71 (a) The basic structure of devices (35). (b) The energy- level diagram of devices (35). 114
Fig. 4 - 72 The luminance-voltage curves of devices (31) and (35). 115
Fig. 4 - 73 The current-voltage curves of devices (31) and (35). 115
Fig. 4 - 74 The current efficiency-voltage curves of devices (31) and (35). 116
Fig. 4 - 75 The EL spectra of devices (31) and (35) at 10 V. 116
Fig. 4 - 76 The CIE coordinates of device (35) at different voltages. 117
Fig. 4 - 77 The pictures of luminescence performance of BGOLED with C6 doped 0.4 wt% in LT-N421 layer. 118

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