单层混合型白色有机电致发光器件的制备与性能提高的研究
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摘要
近年来，平板显示已成为显示技术的发展主流，其中有机薄膜电致发光器件(OLED)由于本身所具有的独特优势，如全固体化、直流低压驱动、可实现柔性显示等，已成为众多平板显示技术中非常有实力的竞争者。如今有机电致发光的研究正向着全色显示方向努力。由于白色有机电致发光器件加入滤色器后可实现全色显示，而且有机白光作为一种超薄光源还可用作液晶显示器的背光源，所以，白色薄膜有机电致发光(OLED)的研究具有非常重要的科学意义和广阔的应用前景。本文主要采用聚合物共混法制备了两种单层混合型白色OLED器件，较全面分析了影响有机电致发光器件发光性能的各项因素，并针对“电极／有机层界面特性”这一较为关键的因素，采用工艺简单的热处理方法提高了白色OLED器件的发光性能。文章最后还采用聚合物和小分子共混的方法制备了一种新型的单层白色OLED器件。
一以PVK为母体掺杂MEH-PPV、OXD-7、PMMA制备了单层混合型白色OLED器件，并详细记述了器件制备的工艺过程，精确测量了这种器件的光电性能。研究了热处理方法对这种结构器件发光性能的影响，确定了最佳热处理条件为180℃、1h。经最佳条件热处理后，器件的启亮电压、发光强度、量子效率等性能显著提高。分析了热处理方法提高这种单层混合型结构器件发光性能的原因。
二以LPPP为母体掺杂MEH-PPV、OXD-7、PMMA制备了单层混合型白色OLED器件，并对这种结构器件在最佳热处理条件(确定为180℃、1h)下进行热处理，提高了器件的发光性能。分析认为热处理提高以LPPP为母体的单层混合型器件发光性能的原因与热处理提高PVK为母体的单层混合型器件发光性能的原因类似。比较了两种结构器件在发光性能方面的差异。
三采用聚合物MEH-PPV、PVK和小分子Balq共混的方法制备了一种新型的单层白色OLED器件。简单分析了聚合物和小分子共混的掺杂机制，精确测量了这种结构器件的光电性能，验证采用该方法制备单层混合型白色OLED器件的可行性。
Recently the organic light-emitting diodes (OLED) has become a predominant contestant in most flat display technology because of its many advantages, such as full solid display; low driven voltage; flexible displays and so on. Now the scientists are making great efforts to realize the full color display. The white OLED devices can easily realize full color display with the sieve implement and be used to LCD's lamp-house. So the white OLED acts as more and more important roles in the area of OLED. We adopt the method of polymer mixed to fabricate two kinds of white organic light-emitting diode with blend single-layer Structure. All factors which affect the luminescent performance of OLED were analyzed in this paper. We considered that the characteristics of the interface between the organic layer and the cathode and the device structure are the crucial factors. In the light of the above analysis, the luminescent performance of white OLED devices were promoted by adopting heat treatment. In the end of this paper, we reported a new type of white OLED device which was fabricated by using polymer doped with organic small molecular material.
1. PVK as host was doped with MEH-PPV, OXD-7 and PMMA. Using it we fabricated whiteorganic light-emitting diode with blend single-layer Structure. Then we particularly record the preparation process of the devices and accurately measured photoelectric characteristics of the devices. Heat treatment at low vacuum on this kind of devices at different temperature and time conditions was performed. After heat treatment, the luminescence performance of the above devices was improved obviously. Our experiments indicated that the optimum heat treatment condition for the MEH-PPV devices is 180℃,1 hour. We analyzed the reason of this phenomenon.
2. LPPP as host is doped with MEH-PPV, OXD-7 and PMMA. Using it we fabricated whiteorganic light-emitting diode with blend single-layer Structure. Heat treatment at low vacuum on this kind of devices at the optimum condition (180℃,1 hour) was performed. After heat treatment, the luminescence performance of the devices was improved obviously. After analyzing, we think the reason of the enhancement of LPPP devices by adopting heat treatment may be similar with that of PVK devices. And we compared the difference of luminescent performance of these two kinds of devices.
3. Polymer MEH-PPV PVK was doped with organic small molecular material Balq. We use itto fabricate a new kind of white organic light-emitting diode with blend single-layer Structure. And we simply analysised the doped mechanism of doped with organic small molecular material, accurately measured photoelectric characteristics of this sort of devices, validated the feasibility of using blend measurement to fabricate white organic light-emitting diode with blend single-layer structure.
一以PVK为母体掺杂MEH-PPV、OXD-7、PMMA制备了单层混合型白色OLED器件，并详细记述了器件制备的工艺过程，精确测量了这种器件的光电性能。研究了热处理方法对这种结构器件发光性能的影响，确定了最佳热处理条件为180℃、1h。经最佳条件热处理后，器件的启亮电压、发光强度、量子效率等性能显著提高。分析了热处理方法提高这种单层混合型结构器件发光性能的原因。
二以LPPP为母体掺杂MEH-PPV、OXD-7、PMMA制备了单层混合型白色OLED器件，并对这种结构器件在最佳热处理条件(确定为180℃、1h)下进行热处理，提高了器件的发光性能。分析认为热处理提高以LPPP为母体的单层混合型器件发光性能的原因与热处理提高PVK为母体的单层混合型器件发光性能的原因类似。比较了两种结构器件在发光性能方面的差异。
三采用聚合物MEH-PPV、PVK和小分子Balq共混的方法制备了一种新型的单层白色OLED器件。简单分析了聚合物和小分子共混的掺杂机制，精确测量了这种结构器件的光电性能，验证采用该方法制备单层混合型白色OLED器件的可行性。
Recently the organic light-emitting diodes (OLED) has become a predominant contestant in most flat display technology because of its many advantages, such as full solid display; low driven voltage; flexible displays and so on. Now the scientists are making great efforts to realize the full color display. The white OLED devices can easily realize full color display with the sieve implement and be used to LCD's lamp-house. So the white OLED acts as more and more important roles in the area of OLED. We adopt the method of polymer mixed to fabricate two kinds of white organic light-emitting diode with blend single-layer Structure. All factors which affect the luminescent performance of OLED were analyzed in this paper. We considered that the characteristics of the interface between the organic layer and the cathode and the device structure are the crucial factors. In the light of the above analysis, the luminescent performance of white OLED devices were promoted by adopting heat treatment. In the end of this paper, we reported a new type of white OLED device which was fabricated by using polymer doped with organic small molecular material.
1. PVK as host was doped with MEH-PPV, OXD-7 and PMMA. Using it we fabricated whiteorganic light-emitting diode with blend single-layer Structure. Then we particularly record the preparation process of the devices and accurately measured photoelectric characteristics of the devices. Heat treatment at low vacuum on this kind of devices at different temperature and time conditions was performed. After heat treatment, the luminescence performance of the above devices was improved obviously. Our experiments indicated that the optimum heat treatment condition for the MEH-PPV devices is 180℃,1 hour. We analyzed the reason of this phenomenon.
2. LPPP as host is doped with MEH-PPV, OXD-7 and PMMA. Using it we fabricated whiteorganic light-emitting diode with blend single-layer Structure. Heat treatment at low vacuum on this kind of devices at the optimum condition (180℃,1 hour) was performed. After heat treatment, the luminescence performance of the devices was improved obviously. After analyzing, we think the reason of the enhancement of LPPP devices by adopting heat treatment may be similar with that of PVK devices. And we compared the difference of luminescent performance of these two kinds of devices.
3. Polymer MEH-PPV PVK was doped with organic small molecular material Balq. We use itto fabricate a new kind of white organic light-emitting diode with blend single-layer Structure. And we simply analysised the doped mechanism of doped with organic small molecular material, accurately measured photoelectric characteristics of this sort of devices, validated the feasibility of using blend measurement to fabricate white organic light-emitting diode with blend single-layer structure.
引文
[1] Boroughs J. H, Bradly D D. Broums C. Light-emitting diodes based on conjugated polymers. Nature, 1990, 374, 539
[2] 杨晓辉．提高空穴传输特性聚合物场致发光亮度和效率的探索．博士毕业论文．1999，7：50
[3] 卢志云，谢明贵等．聚合物电致发光材料节器件[J]．材料导报，2000，14，8：50
[4] Junji Kido, Wataru Ikeda. White-Light-Emittiag Electroluminescent Device Using Lantthanide Complexes[J]. Jpn. J. Appl. Phys. 35(1996)
[5] Boroughs J. H, Bradly D D. Broums C. Light-emitting diodes based on conjugated polymers. Nature, 1990, 374, 539
[6] Cimrova V, Scherf U, Nether D. Microcavity devices based on a ladder-type poly(p-phenylere) emitting blue, green and red light. App. Phys. Lett, 1996, 69, 608
[7] 黄春辉 李富友 黄岩谊．光电功能超薄膜．2001(1) 北京大学出版社 北京 238—298
[8] Shi Jianmin, Tang C W. Doped organic electroluminescent devices with improved stability. App. Phys. Lett, 1997, 70, 1665
[9] VanSlyke S. A, Chen C H, Tang C. W. Organic electroluminescent devices with improved stability[J]. Appl. Phys. Lett., 1996, 69, 2160-2162
[10] V. Bulovic, P. E. Burrows, S. R. Forrest, Electroluminescence (Ⅰ)64 (2000) 262.
[11] S. Tasch, J. Gao, F. P. Wenzl, L. Holzer, U. Scherf, K. M. ullen, A. J. Heeger, G. Leising, Electrochem. Solid State Lett. 2(1999) 303.
[12] Howard WE, Prache OF, IBM journal of research and development, 2001, 45(1), 115
[13] N. Takada, T. Tsutui, S. Saito, App. Phys. Lett, 1993, 65, 2032
[14] C. W. Tang, D. J. Williams, J. C. Chang, U. S. Patent No. 1994, 5, 294, 870
[15] Y. Ohmori, A. Fujii, et al. Novel Characteristics of Electroluminescent Diode with Organic Multiple-Quantum-Well Structure. Jpn. J. Appl. Phys., 1995, 34: 3790-3793
[16] A. Fujii, M. Yoshida, Y. Ohmori, and K. Yoshino. Color-Variable Electroluminescent Diode with Single Quantum Well Structure Utilizing 8-Hydroxyquinoline Aluminum and Aromatic Diamine. Jpn. J. Appl. Phys., 1995, 34, L499-L502
[17] H. Y. An, B. J. Chen, et al. Exciton confinement in organic multiple quantum well structures. J. Phys D: Appl. Phys., 1998, 31: 1144-1148
[18] A. Dodabalapur, L. J. Rothberg, T. M. Miller. Color variation with electroluminescent organic semiconductors in multimode resonant cavities. Appl. Phys. Lett., 1994, 65: 2308-2610
[19] A. Dodabalapur, L. J. Rothberg, et al. Microcavity effects in organic semiconductors. Appl. Phys. Let, 1994, 64: 2486-2488
[20] 高观志，黄维著，雷清泉译．固体中的电运输．1991年第一版，科学出版社．
[21] N. Takada, T. Tsutsui, S. Saito, E. Ogino, App. Phys. Lett, 1994, 65, 1868
[22] N. Tessler, G. L. Denton, R. H. Friend, Nature 1996, 382-595
[23] Y. Hamada, T. Sano, H. Fujii, Y. Nishio, Jpn. J. App. Phys. 1996, 35, L1339
[24] 阎金良，朱长纯等．可溶性聚合物发光器件的电致发光．西安交通大学学报[J]．2000，34，10
[25] Y. Cao, I. D. Park, G. Yu, and A. J. Heeger. Improved quantum efficiency for electroluminescence in semiconducting polymers, Nature, 1999, 297, 414-417
[26] Y. F. Li, Y. Cao, et al. Electrochemical properities of luminescence polymers and polyumer light-emitting electrochemical cells[J]. Synth. Met, 1999, 99, 243
[27] Eley, D. D. and Willis, M. R., in Symposium on Electrical Conductivity in Organic Solids(eds. H. Sallmann and M. Silver), Wiley Interscience, NewYork, 1961, 257, 76
[28] 李娟，华玉林，冯秀兰，等 “热处理对单层聚合物电致发光器件性能的影响” 光电子·激光 第12卷 第12期 1218(2001)
[29] 杨晓辉．提高空穴传输特性聚合物场致发光亮度和效率的探索．博士毕业论文．1999，7：50
[30] Hua YuLin, Feng XiuLan, Wang WanLu. Organic Electroluminescent Device with Blue Emitting Light Driven at Low Voltage[J]. Chinese Journal Of Luminescene, 1998, 19: 149-151(in Chinese)
[31] D. Braun, A. J. Heeger, Appl. Phys. Lett, 1991, 58, 1982
[32] A. Jenekhe, X. Zhang, X. L. Chen, V. E. Choong, Y. Gao, B. R. Hsieh, Chem. Mater. 1997, 9, 409
[33] 蒋雪茵，张志林等．稳定的兰色及白色有机薄膜电致发光器件[J]．发光学报 2000，21，4
[34] Magnus Granstrom, Olle inganas. White light emission from a polymer blend light emitting diode[J]. Appl. Phys. Lett. 1996, 68(2), 8
[35] 吴晓明，华玉林，罗经国等 “有机电致发光器件量子效率的测量系统建立及其应用研究” 发光学报，23(6)，2002
[36] J. McElvan, H. Antoniadis. Formation and grows of black spots in organic light-emitting diodes[J]. J. Appl. Phys. Lett, 1996, 80(10)
[37] Tae-Woo Lee and O OK Park. The Effect of Different Heat Treatments on the Luminescence of Polymer Light-Emitting Diodes[J]. Adv. Mater, 2OOO, 12, NO.11: 801-804
[38] Lee-M. Do, Mitsuaki Oyamada, Amane Koike, etal. Morphological Change In the Degradation of AL Electrode Surface of Electroluminescent Devices by
[39] Vandim N. Sawate'ev, AharonV. Yakimov Degradation of nonencapsulated polymer-based light-emitting diodes: Noise and morphology(J). Appl. Phys. Lett, 1997, 71(23): 3344-3346
[40] Hua YuLin, Feng XiuLan, Wang WanLu. Organic Electroluminescent device with Blue Emitting Light Driven at Low Voltage[J]. Chinese Journal of Luminescene, vol.19. (1998)149-151.
[41] Scherf and K Mullen, A soluble ladder polymer via bridging of functionalized poly(p-phenylene) precursors, Makromol. Chem. Rapid Comm., 1991, 12: 489-493
[42] 刘星元，李文连，虞家琪，赵宇，有机薄膜电致发光的形成过程，发光学报，1996，17(4)：376-377
[43] Yan M, Pothbers LJ, Kwock E W, et al, Interchain excitation in conjugated polymers[J], Phys. Rev. Lett., 1995, 75: 1992-1995
[44] 廖克俊，王万录，王蜀霞，有机高分子聚合物LPPP异质结构微腔调谐器可靠性的研究，光电子技术，2000，20(2)，107-110
[45] 李娟 华玉林 冯秀兰，等 “热处理对单层聚合物电致发光器件性能的影响” 光电子·激光 第12卷 第12期 1218(2001)
[46] 李娟 华玉林 冯秀兰，等 “热处理提高蓝色有机电致发光器件性能的研究” 光电子·激光 第13卷 第11期 1101(2002)
[47] J. kido, K. Hongawa, K. Okuyama, K. Nagai, White light-emitting organic electroluminesecent devices using the poly(N-vinylcarbazole) emitter layer doped with three fluorescent dyes, Appl. Phys. Lett, 1994, 64(7), 815-817.
[48] Xue Yin Jiang, Zhi Lin Zhang, Bu Xin Zhang, Wen Qing Zhu, Shao Hong Xu, Stable and Current independent white-emitting organic diode, Synthetic Metals, 2002, 129, 9-13
[49] Norikazu Nakamura, Shinichi Wakabayashi, Keiichi Miyairi, Tsuneo Fujii, A Novel Blue Light Emitting Material Prepared from 2-(o-hydrophenyl)benzoxazole, Chemistry Letters, 1994, pp1741-1742
[50] Wang Rongqiu, Li Jingjian, Cai Shengmin, Liu Zhongfan, The Time Dependent Red Shift Phenomenon of Visible Electroluminescence of Porous Silicon, Electrochemistry, 1998, 4(1), 60-65(in Chinese)
[51] Magnus Granstrm, Olle Inganas, White light emission from a polymer blend light emitting diode, Appl. Phys. Lett. 1996, 68(2), 147-149
[52] Z. Q. Gao, C. S. Lee, I. Bello, S. T. Lee, White light electroluminesecent from a hole-transporting layer of mixed organic materials, Synthetic Metals, 2000, 111-112, 39-42
[53] Junji Kido, Wataru Ikeda, Masato Kimcra, Katsutoshi Nagai, White-light-emitting organic electro- luminescent device using the Lanthanide complexes, Jpn. J. Appl. Phys., 1996, 35(3), L394-396
[54] Liu Zugang, Helena Nazare, white organic light-emitting diodes from both hole and electron transport layers, Synthetic Metals, 2000, 111-112, 47-51
[55] 黄春辉，李富友，黄岩谊，光电功能超薄膜，北京大学出版社，2001，p251
[56] Hamada, Y.; Sano, T.; Fujii, H.; Nishio, Y.; Takahashi, H.; Shibata, K., white light-emitting material for organic electro- luminesecent devices, Jpn. J. Appl. Phys. 1996, 35, L1339
[2] 杨晓辉．提高空穴传输特性聚合物场致发光亮度和效率的探索．博士毕业论文．1999，7：50
[3] 卢志云，谢明贵等．聚合物电致发光材料节器件[J]．材料导报，2000，14，8：50
[4] Junji Kido, Wataru Ikeda. White-Light-Emittiag Electroluminescent Device Using Lantthanide Complexes[J]. Jpn. J. Appl. Phys. 35(1996)
[5] Boroughs J. H, Bradly D D. Broums C. Light-emitting diodes based on conjugated polymers. Nature, 1990, 374, 539
[6] Cimrova V, Scherf U, Nether D. Microcavity devices based on a ladder-type poly(p-phenylere) emitting blue, green and red light. App. Phys. Lett, 1996, 69, 608
[7] 黄春辉 李富友 黄岩谊．光电功能超薄膜．2001(1) 北京大学出版社 北京 238—298
[8] Shi Jianmin, Tang C W. Doped organic electroluminescent devices with improved stability. App. Phys. Lett, 1997, 70, 1665
[9] VanSlyke S. A, Chen C H, Tang C. W. Organic electroluminescent devices with improved stability[J]. Appl. Phys. Lett., 1996, 69, 2160-2162
[10] V. Bulovic, P. E. Burrows, S. R. Forrest, Electroluminescence (Ⅰ)64 (2000) 262.
[11] S. Tasch, J. Gao, F. P. Wenzl, L. Holzer, U. Scherf, K. M. ullen, A. J. Heeger, G. Leising, Electrochem. Solid State Lett. 2(1999) 303.
[12] Howard WE, Prache OF, IBM journal of research and development, 2001, 45(1), 115
[13] N. Takada, T. Tsutui, S. Saito, App. Phys. Lett, 1993, 65, 2032
[14] C. W. Tang, D. J. Williams, J. C. Chang, U. S. Patent No. 1994, 5, 294, 870
[15] Y. Ohmori, A. Fujii, et al. Novel Characteristics of Electroluminescent Diode with Organic Multiple-Quantum-Well Structure. Jpn. J. Appl. Phys., 1995, 34: 3790-3793
[16] A. Fujii, M. Yoshida, Y. Ohmori, and K. Yoshino. Color-Variable Electroluminescent Diode with Single Quantum Well Structure Utilizing 8-Hydroxyquinoline Aluminum and Aromatic Diamine. Jpn. J. Appl. Phys., 1995, 34, L499-L502
[17] H. Y. An, B. J. Chen, et al. Exciton confinement in organic multiple quantum well structures. J. Phys D: Appl. Phys., 1998, 31: 1144-1148
[18] A. Dodabalapur, L. J. Rothberg, T. M. Miller. Color variation with electroluminescent organic semiconductors in multimode resonant cavities. Appl. Phys. Lett., 1994, 65: 2308-2610
[19] A. Dodabalapur, L. J. Rothberg, et al. Microcavity effects in organic semiconductors. Appl. Phys. Let, 1994, 64: 2486-2488
[20] 高观志，黄维著，雷清泉译．固体中的电运输．1991年第一版，科学出版社．
[21] N. Takada, T. Tsutsui, S. Saito, E. Ogino, App. Phys. Lett, 1994, 65, 1868
[22] N. Tessler, G. L. Denton, R. H. Friend, Nature 1996, 382-595
[23] Y. Hamada, T. Sano, H. Fujii, Y. Nishio, Jpn. J. App. Phys. 1996, 35, L1339
[24] 阎金良，朱长纯等．可溶性聚合物发光器件的电致发光．西安交通大学学报[J]．2000，34，10
[25] Y. Cao, I. D. Park, G. Yu, and A. J. Heeger. Improved quantum efficiency for electroluminescence in semiconducting polymers, Nature, 1999, 297, 414-417
[26] Y. F. Li, Y. Cao, et al. Electrochemical properities of luminescence polymers and polyumer light-emitting electrochemical cells[J]. Synth. Met, 1999, 99, 243
[27] Eley, D. D. and Willis, M. R., in Symposium on Electrical Conductivity in Organic Solids(eds. H. Sallmann and M. Silver), Wiley Interscience, NewYork, 1961, 257, 76
[28] 李娟，华玉林，冯秀兰，等 “热处理对单层聚合物电致发光器件性能的影响” 光电子·激光 第12卷 第12期 1218(2001)
[29] 杨晓辉．提高空穴传输特性聚合物场致发光亮度和效率的探索．博士毕业论文．1999，7：50
[30] Hua YuLin, Feng XiuLan, Wang WanLu. Organic Electroluminescent Device with Blue Emitting Light Driven at Low Voltage[J]. Chinese Journal Of Luminescene, 1998, 19: 149-151(in Chinese)
[31] D. Braun, A. J. Heeger, Appl. Phys. Lett, 1991, 58, 1982
[32] A. Jenekhe, X. Zhang, X. L. Chen, V. E. Choong, Y. Gao, B. R. Hsieh, Chem. Mater. 1997, 9, 409
[33] 蒋雪茵，张志林等．稳定的兰色及白色有机薄膜电致发光器件[J]．发光学报 2000，21，4
[34] Magnus Granstrom, Olle inganas. White light emission from a polymer blend light emitting diode[J]. Appl. Phys. Lett. 1996, 68(2), 8
[35] 吴晓明，华玉林，罗经国等 “有机电致发光器件量子效率的测量系统建立及其应用研究” 发光学报，23(6)，2002
[36] J. McElvan, H. Antoniadis. Formation and grows of black spots in organic light-emitting diodes[J]. J. Appl. Phys. Lett, 1996, 80(10)
[37] Tae-Woo Lee and O OK Park. The Effect of Different Heat Treatments on the Luminescence of Polymer Light-Emitting Diodes[J]. Adv. Mater, 2OOO, 12, NO.11: 801-804
[38] Lee-M. Do, Mitsuaki Oyamada, Amane Koike, etal. Morphological Change In the Degradation of AL Electrode Surface of Electroluminescent Devices by
[39] Vandim N. Sawate'ev, AharonV. Yakimov Degradation of nonencapsulated polymer-based light-emitting diodes: Noise and morphology(J). Appl. Phys. Lett, 1997, 71(23): 3344-3346
[40] Hua YuLin, Feng XiuLan, Wang WanLu. Organic Electroluminescent device with Blue Emitting Light Driven at Low Voltage[J]. Chinese Journal of Luminescene, vol.19. (1998)149-151.
[41] Scherf and K Mullen, A soluble ladder polymer via bridging of functionalized poly(p-phenylene) precursors, Makromol. Chem. Rapid Comm., 1991, 12: 489-493
[42] 刘星元，李文连，虞家琪，赵宇，有机薄膜电致发光的形成过程，发光学报，1996，17(4)：376-377
[43] Yan M, Pothbers LJ, Kwock E W, et al, Interchain excitation in conjugated polymers[J], Phys. Rev. Lett., 1995, 75: 1992-1995
[44] 廖克俊，王万录，王蜀霞，有机高分子聚合物LPPP异质结构微腔调谐器可靠性的研究，光电子技术，2000，20(2)，107-110
[45] 李娟 华玉林 冯秀兰，等 “热处理对单层聚合物电致发光器件性能的影响” 光电子·激光 第12卷 第12期 1218(2001)
[46] 李娟 华玉林 冯秀兰，等 “热处理提高蓝色有机电致发光器件性能的研究” 光电子·激光 第13卷 第11期 1101(2002)
[47] J. kido, K. Hongawa, K. Okuyama, K. Nagai, White light-emitting organic electroluminesecent devices using the poly(N-vinylcarbazole) emitter layer doped with three fluorescent dyes, Appl. Phys. Lett, 1994, 64(7), 815-817.
[48] Xue Yin Jiang, Zhi Lin Zhang, Bu Xin Zhang, Wen Qing Zhu, Shao Hong Xu, Stable and Current independent white-emitting organic diode, Synthetic Metals, 2002, 129, 9-13
[49] Norikazu Nakamura, Shinichi Wakabayashi, Keiichi Miyairi, Tsuneo Fujii, A Novel Blue Light Emitting Material Prepared from 2-(o-hydrophenyl)benzoxazole, Chemistry Letters, 1994, pp1741-1742
[50] Wang Rongqiu, Li Jingjian, Cai Shengmin, Liu Zhongfan, The Time Dependent Red Shift Phenomenon of Visible Electroluminescence of Porous Silicon, Electrochemistry, 1998, 4(1), 60-65(in Chinese)
[51] Magnus Granstrm, Olle Inganas, White light emission from a polymer blend light emitting diode, Appl. Phys. Lett. 1996, 68(2), 147-149
[52] Z. Q. Gao, C. S. Lee, I. Bello, S. T. Lee, White light electroluminesecent from a hole-transporting layer of mixed organic materials, Synthetic Metals, 2000, 111-112, 39-42
[53] Junji Kido, Wataru Ikeda, Masato Kimcra, Katsutoshi Nagai, White-light-emitting organic electro- luminescent device using the Lanthanide complexes, Jpn. J. Appl. Phys., 1996, 35(3), L394-396
[54] Liu Zugang, Helena Nazare, white organic light-emitting diodes from both hole and electron transport layers, Synthetic Metals, 2000, 111-112, 47-51
[55] 黄春辉，李富友，黄岩谊，光电功能超薄膜，北京大学出版社，2001，p251
[56] Hamada, Y.; Sano, T.; Fujii, H.; Nishio, Y.; Takahashi, H.; Shibata, K., white light-emitting material for organic electro- luminesecent devices, Jpn. J. Appl. Phys. 1996, 35, L1339