臺灣博碩士論文加值系統

本論文中，我們利用此結構：ITO/PEDOT/PF/LiF/Ag/IZO來製作全透式有機高分子發光二極體。對有機發光二極體來說封裝技術是很重要的。有機發光二極體主要的劣化原因來自於水氣與氧氣滲入到元件中與有機層反應形成非發光區域進而造成元件效率下降。因此，有機發光二極體需要額外封裝層來保護元件。然而，單一層無機薄膜封裝層並不足以抵擋外界水器入侵到元件中且其壽命成效無法滿足有機發光二極體的要求。所以以無機/無機、無機/有機薄膜堆疊多層封裝方式便被發展出來。
我們利用氧化鋅薄膜具有高穿透度和可以抵擋紫外光的優點同時結合樹脂用來當作封裝層，可以有效保護有機發光二極體且其電性行為與玻璃封裝元件相類似。此結果說明有效率抵擋水氣滲入元件並且沒有暗點形成。其元件壽命可長達100小時可以與玻璃封裝元件相同。另一種以氧化鋅結合用原子層化學氣相沉積氧化鋁與二氧化鉿多層疊加來當作有機發光二極體的封裝層，其元件壽命有85小時效果比起沒有封裝的元件改善了50倍之多。

In this thesis, we used the structure of ITO/PEDOT/PF/LiF/Ag/IZO to fabricate the fully transparent PLED devices. The encapsulation technology is critical for OLEDs and PLEDs. A major reason for the degradation of OLEDs and PLEDs due to moisture or oxygen ingress is the formation of non-emissive dark spots. So, the PLEDs need the additional passivetion layer to protect itself. However, a single inorganic thin film is not sufficiently dense to protect the OLEDs and PLEDs from permeation by moisture and oxygen and the performance of a single barrier layer is order of magnitude short of the requirements for OLEDs. Thus, a multilayered passivation composed of inorganic/inorganic or inorganic/polymer coating layers has been developed .We used the advantages of ZnO thin film such as high transparent in the visible light region and blocking ultraviolet combines the UV-cured epoxy resin to fully transparent PLEDs. The ZnO/UV-cured epoxy resin passivation layer can effectively protect PLEDs such a passivated device exhibited similar electrical behavior to a glass-encapsulated device. This result indicated that the fabrication process for forming the passivation layer did not influence the performance of the device. The lifetime of both devices was almost equal (about 100 hours), and no dark spots were formed in the optical images of electroluminescence over time. Moreover, another encapsulation method that the Al2O3/HfO2/Al2O3…HfO2 stacked multi-layers deposited onto the ZnO barrier layer by ALD put in use to the PLEDs encapsulation. The lifetime can improve 50 times (about 85 hours) comparing the PLEDs without passivation layer.

Contents
指導教授推薦書…………………………………………………………..
口試委員審定書…………………………………………………………..
授權書…………………………………………………………………...iii
誌謝……………………………………………………………………...iv
中文摘要…………………………………………………………………v
Abstract……………………………………………………………….....viContents…………………………………………………………………vii
Figure of contents………………………………………………………..ix
Table of contents………………………………………………………..xii
Chapter I Introduction 1
1-1 Previous remark 1
1-2 Organic light-emitting diodes 2
1-2-1 Mechanism of light emitting 2
1-2-2 The Structure of OLEDs 3
1-3 The application of TCO in OLEDs and PLEDs 5
1-3-1 Thin Metal Film 5
1-3-2 Transparent conductive oxide films 6
1-4 Degradation mechanism of the OLEDs and PLEDs 12
1-5 Barrier layer technology 15
1-6 Research motivation 17
Chapter II Experiment 24
2-1 Materials 25
2-2 Experimental procedures 26
2-3 Measurements 30
Chapter III Result and Discussion 35
3-1 The analysis of ZnO thin films 35
3-1-1 the surface morphology of ZnO thin films 35
3-1-2 The structure of ZnO thin films 35
3-1-3 The optical characteristics of ZnO thin films 37
3-2 The photoelectric characteristics of fully transparent PLEDs with ZnO-based passivation layer 40
Chapter IV Conclusion 67
Reference 69
















Figure of contents
Figure 1-1: The schematic of the theorem of electroluminescence. 20
Figure 1-2: The schematic of the light-emitting mechanism. 21
Figure 1-3: (a) Bottom emission structure, (b) top emission structure and (c) fully transparent structure of OLED devices. 22
Figure 1-4: A crystal system and unit cell of ZnO. 23
Figure 2-1: The normalized PL spectrum of emitting polymer PF. 31
Figure 2-2: The schematic diagram of the thermal evaporation deposition system. 32
Figure 2-3: The schematic diagram of the RF sputtering deposition system. 33
Figure 2-4: The passivated structures of PLEDs, (a)glass passivated, (b)ZnO/UV-cured epoxy passivated and (c) ZnO/Al2O3/HfO2/Al2O3…HfO2 stacked multi-layers passivated. 34
Figure 3-1: The AFM images of ZnO films with different thickness of (a) 50 nm, (b) 100 nm, and (c) 250 nm. 50
Figure 3-2: (a) XRD patterns and (b) FWHM of XRD peaks and crystal sizes for ZnO films with different thickness. 51
Figure 3-3: The transmittance spectra of ZnO films with different thickness. 52
Figure 3-4: The plots of (αhv)2 vs photon energy and (inset) optical band energy for ZnO films with different thickness. 53
Figure 3-5: The absorbance of ZnO films with different thickness. 54
Figure 3-6: Photographed images of a light-emitting of the ITO/ZnO/UV-cured epoxy passivated PLED. 54
Figure 3-7: The XRD patterns of ZnO films with different thickness deposited onto the ITO surface. 55
Figure 3-8: The XRD patterns of (a) ITO, Al2O3, IZO film, and (b) ZnO films with different thickness deposited onto the IZO surface. 56
Figure 3-9: (a) Total luminance (included top and bottom) of fully transparent PLEDs with different structure, (b) luminance measured from top cathode vs current density. 57
Figure 3-10: The transmittance of ITO, IZO cathode and ITO encapsulated with Al2O3/ZnO/UV-cured epoxy resin. 58
Figure 3-11: (a) J-V characteristics and (b) current efficiency (from top cathode) of fully transparent PLEDs with ITO, IZO cathode and PLEDs encapsulated passivation layer with Al2O3/ZnO/UV-cured epoxy resin. 59
Figure 3-12: The PL spectra of PF film and EL spectra of PLEDs with ITO and IZO cathode. 60
Figure 3-13: (a) J-V characteristics and (b) transmittance (from top cathode side) of a series passivation layer of IZO cathode based PLEDs. 61
Figure 3-14: (a) Luminance and (b) current efficiency of a series passivation layer of IZO cathode based PLEDs. 62
Figure 3-15: The lifetimes of the PLED devices passivated by Al2O3/ZnO/UV-cured epoxy resin, glass lid, ZnO thin film, ZnO/UV-cured epoxy resin, and stacked multi-pairs of Al2O3/HfO2 thin film layers. 63
Figure 3-16: The optical images of the electroluminescence over time for the three devices. PLEDs passivated with (a) no passivation layer, (b) glass, and (c) ZnO/UV-cured epoxy resin. 64
Figure 3-17: The normalized EL spectra of the PLEDs passivated with ZnO/UV-cured epoxy resin films and ZnO/Al2O3/HfO2/Al2O3…HfO2 stacked multi-layers. 65
Figure 3-18: (a) The lifetime of PLEDs passivated with gas barriers by ALD at different temperature and (b) the photographed images of emitting area. 66


















Table of contents
Table 1-1: The comparison of characteristics of OLED and other traditional displays. 19
Table 3-1: The AFM-RMS roughness of ZnO with various thickness. 50
Table 3-2: The driven current density and initial luminance was measured from a series structure of PLEDs. 63
Table 3-3: The EL peak and FWHM was measured form the top and bottom side of PLEDs, and the refractive index of different film. 65

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