基于界面修饰与纳米结构的有机电致发光器件的性能研究
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摘要
聚合物电致发光器件（polymer light-emitting diodes, PLEDs）作为新型的固体照明设备和显示器件具有更好的性能优势。与传统的发光照明和显示方式无机发光二极管（LED）、液晶显示器件（LCD）和等离子体显示器件（PDP）等比较，PLEDs具有自发光、快速响应、全固态器件、超薄体积、制备工艺简单、制作成本低，尤其是器件具有柔性和全溶液制备方法的特点，既适合大面积的生产从而降低成本，又适合在各种特殊表面和极端情况使用，PLEDs是公认为21世纪最理想和最有使用前景的照明和显示技术。但是目前在大尺寸的商业化应用上还存在一些问题需要解决，例如由于PLEDs内部电荷载流子的注入和传输不平衡导致的器件发光效率还不够理想，而且由于目前普遍使用的透明导电阳极氧化铟锡（ITO）使用了稀土元素铟（indium）导致ITO的成本和价格不断提高，所以控制整个PLEDs的生产成本越来越困难。针对这两方面的问题，我们通过使用新材料和界面修饰的方法改善器件的发光性能，同时通过使用新型纳米材料和纳米结构取代目前广泛使用的ITO透明导电阳极，制备高性能的三基色和基于三基色和两种互补色的白光磷光PLEDs，本论文在这两个方面进行了一系列的探索性和创新性的工作，具体包括：
1．通过溶液旋涂的方法，在溶液中掺杂oligo(ethylene oxide)(PEO-DME)，从而制备了高效率蓝光磷光PLEDs，器件中使用poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)旋涂在透明导电阳极indium tin oxide (ITO)上作为空穴注入材料，氟化铯/铝作为电子注入电极。单层活性发光层使用poly(9-vinylcarbazole)(PVK)作为主体材料，bis[(4,6-difluorophenyl)-pyridinato-N,C2](picolinato)Ir(Ⅲ)(FIrpic)作为蓝光磷光掺杂染料，1,3-bis[(4-tert-butylphenyl)-1,3,4-oxidiazolyl]phenylene (OXD-7)作为电子传输材料。 PEO-DME的掺杂比例为5-10wt%时可以有效的降低电子和空穴的注入势垒。当发光亮度为2500cd/m2时，器件达到最大的电流效率为26.5cd/A。器件取得高性能的原因在于PEO-DME的掺杂会使这种材料与铝电极之间产生特殊的相互作用，从而改善了电荷载流子在界面的注入，另外PEO-DME的掺杂改变了器件内部的电场分布，从而导致电荷载流子的迁移率提高。
2．通过在单层发光活性层中掺杂使用poly(ethylene glycol) dimethyl ether(PEG-DME)，制备了高性能白光磷光PLEDs。根据白光的颜色组成不同，器件的发光活性层中分别掺杂了PVK、OXD-7和两种互补色或者三基色的磷光染料。掺杂的PEG-DME可以有效的增强电子注入和传输，同时平衡电子和空穴的密度。基于两种互补色的白光PLEDs在正向观测亮度为1800cd/m~2时最大的电流效率为17.5cd/A，基于三基色的白光PLEDs在正向观测亮度为3000cd/m~2时最大的电流效率为35.7cd/A，即使发光亮度高达30000cd/m~2时，器件的电流效率仍然可以达到30cd/A以上。器件的高电流效率归因于提高了阴极向聚合物发光活性层的电子注入能力，电荷传输能力和PEG-DME对长波长发光峰的增强作用。另外，器件稳定的电流效率是由于单载流子器件中电荷载流子注入和传输的增强以及激子复合发光区域的移动导致的三重态激子-极化子湮灭和电场导致的三重态激子猝灭减弱。
3．通过溶液法制备银纳米线（AgNW）和AgNW-聚合物复合电极基板，制备了蓝光、绿光和红光磷光PLEDs。基于这类金属纳米结构电极基板的发光器件获得了比传统ITO/玻璃基板上更高的发光效率。蓝光PLEDs在亮度为1400cd/m~2时，电流效率达到21.5cd/A，在发光亮度为450cd/m~2到5500cd/m~2时，器件的效率维持在20-21.5cd/A这个很小的范围之内，即使发光亮度达到10000cd/m~2时，效率仍然可以达到18.5cd/A。根据不同发光颜色，器件的结构略有不同，基于AgNW-聚合物复合电极基板的蓝光、绿光和红光器件的发光效率比基于ITO/玻璃基板的器件高20-50%。三种不同种颜色器件性能的提高归因于AgNW-聚合物复合电极基板具有比ITO/玻璃基板更高的透过率，尤其是在短波长区域和蓝光区域，同时复合电极基板中的AgNW是作为多光子散射中心存在，可以提高基板的出光率。另外，蓝光PLEDs器件可以经过10次到100次的反复弯曲，并且曲率直径只有1.5mm。进过计算，根据器件弯曲的方向不同，发光器件受到的内部压力或者表面张力可以达到5%，并且器件的发光性能变化不大，在器件反复弯曲100次后，电流效率可以保持在初始效率的87%。
4．通过使用AgNW-聚合物复合电极基板制备了高性能磷光白光PLEDs，同时利用复合电极基板提高了白光器件的发光效率和光提取效率。基于两种互补色的白光PLEDs在正向观测亮度为4500cd/m~2时最大的电流效率为20.3cd/A，基于三基色的白光PLEDs在正向观测亮度为4000cd/m~2时最大的电流效率为42.3cd/A，相对于使用ITO/玻璃基板的传统器件，器件的发光效率分别提高了35%和41%。即使在发光亮度提高到10000cd/m~2以上，白光器件的发光效率依然分别保持在20cd/A和40cd/A。白光器件的高电流效率归因于AgNW-聚合物复合电极基板有效提取了传统器件中透明导电电极ITO中被陷阱的40-50%的光波导模式，大大提高了出光效率，另外复合电极基板表面和掩埋在聚合物主体材料内部的AgNW可以通过光散射的方式提取对比器件中玻璃基板中陷阱的光波导模式。此类白光器件同样具有性能优异的弯折性能，在反复弯折测试中，器件张力或者压力为5%的时候，器件的性能几乎不变。
Polymer light-emitting diodes (PLEDs) as the solid lighting and display panel,compared with inorganic LED, liquid crystal display (LCD), have many advantages, e.g.self-emission, fast response, full solid device, super-thin thickness, low cost, especiallyflexible and solution processed. PLEDs are considered as the most ideal and potentiallighting technology in21stcentury. However, now there are also some problems toresolve from large scale commercial application such as low luminous efficiency andhigh fabrication cost due to the imbalance of charge carrier injection and transport andthe cost of commercial transport conductive anode indium-tin oxide (ITO) wasincreasing. Aiming at those problems, some new and systematic works have been doneto focus on the fabrication process to obtain high performance device usingmodification and novel nanostructure electrode to replace the ITO anode with highluminous efficiency for phosphorescent PLEDs.
1. Solution processed blue electrophosphorescent PLEDs have been fabricatedcontaining an oligo(ethylene oxide)(PEO-DME) additive to enhance theelectroluminescence efficiency. The device uses poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) coated on indium tin oxide as the hole injectionelectrode, cesium fluoride/aluminum as the electron injection electrode. The singleemissive layer is a blend of poly(9-vinylcarbazole)(PVK) as the host,bis[(4,6-difluorophenyl)-pyridinato-N,C2](picolinato)Ir(III)(FIrpic) as thephosphorescent dopant, and1,3-bis[(4-tert-butylphenyl)-1,3,4-oxidiazolyl]phenylene(OXD-7) to enhance electron transporting. The addition of an oligo(ethylene oxide) at5-10wt%effectively lowers both the electron and hole injection barriers. The maximumcurrent efficiency obtained was26.5cd/A at an emission brightness of2500cd/m~2. Thehigh performance is due to (i) improved charge carrier injection at the interfaceresulting from specific interfacial interactions between PEO-DME and aluminum,(ii)improved charge carrier transporting ability and high electric field resulting fromPEO-DME doping.
2. White polymer phosphorescent light-emitting diodes (WPLEDs) have been fabricated employing poly(ethylene glycol) dimethyl ether (PEG-DME) blended in thesingle active layer to enhance the emission efficiency. The devices have a simplesandwich architecture of ITO/PEDOT:PSS/emissive layer/CsF/Al. The emissive layeruses a blend of PVK, OXD-7, two or three phosphorescent dopants with complementarycolors. The addition of PEG-DME enhances electron injection, transport, and thebalance of densities of electrons and holes. The measured current efficiency in the frontviewing direction is17.5cd/A at1800cd/cm~2for the two complementary WPLEDs,and35.7cd/A at3000cd/m~2for the three complementary color WPLEDs. The currentefficiencies remain high even at brightness levels up to30,000cd/m~2. The high currentefficiency is ascribed to the improved electron injection ability from the metal cathode,the enhanced charge carrier transport ability and the enhanced red emitting intensity byblending with PEG-DME. Also the low roll-off of the current efficiency was due to thelower triplet-polaron annihilation and the electric field-induced triplet excitonquenching by increased charge carrier transport in unipolar device and movedrecombination zone. The improved charge carrier injection at the interface and theenhanced charge carrier transport were resulted from specific interfacial interactionsbetween PEG-DME and aluminum and higher electric field by blending withPEG-DME.
3. We report the demonstration of blue, green, and red electrophosphorescentPLEDs fabricated on silver nanowire (AgNW) polymer composite electrode. Thecurrent efficiency of the ITO-free blue PLEDs falls in the narrow range of20.0-21.5cd/A in the brightness range of450-5500cd/m~2, and decreases slightly to18.5cd/A at10,000cd/m~2. The devices are20%-50%more efficient than control devices onITO/glass. The current efficiency of the green and red phosphorescent PLEDs was alsoenhanced by20-30%. The improved performance can be attributed to the highertransparency of the AgNW electrode than ITO/glass in the blue region, as well asphoton scattering on the surface of AgNWs in the composite electrode that enhanceslight out-coupling efficiency. The blue PLEDs can be repeatedly bent to1.5mm radiusconcave or convex with calculated strain in the emissive layer to be5%(tensile orcompressive).
4. Phosphorescent WPLEDs have been fabricated employing AgNW-polymercomposite substrate to enhance the light out-coupling and emission efficiency. The current efficiency in the front viewing direction is20.3cd/A for the two complementarycolors devices and42.3cd/A at4000cd/cm~2for the three primary colors devices, theresults are35%and41%higher than that of a conventional WPLEDs used as acomparison, respectively. The high current efficiency is ascribed to the improved lightout-coupling and the waveguided light in ITO and glass substrate could extract in to airfrom light scattering of the AgNW network on the surface and embedded in the polymercomposite. The WPLEDs on the composite substrate are highly flexible and be bent to amaximum5%compressive strain with little decrease on device efficiency.
1．通过溶液旋涂的方法，在溶液中掺杂oligo(ethylene oxide)(PEO-DME)，从而制备了高效率蓝光磷光PLEDs，器件中使用poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)旋涂在透明导电阳极indium tin oxide (ITO)上作为空穴注入材料，氟化铯/铝作为电子注入电极。单层活性发光层使用poly(9-vinylcarbazole)(PVK)作为主体材料，bis[(4,6-difluorophenyl)-pyridinato-N,C2](picolinato)Ir(Ⅲ)(FIrpic)作为蓝光磷光掺杂染料，1,3-bis[(4-tert-butylphenyl)-1,3,4-oxidiazolyl]phenylene (OXD-7)作为电子传输材料。 PEO-DME的掺杂比例为5-10wt%时可以有效的降低电子和空穴的注入势垒。当发光亮度为2500cd/m2时，器件达到最大的电流效率为26.5cd/A。器件取得高性能的原因在于PEO-DME的掺杂会使这种材料与铝电极之间产生特殊的相互作用，从而改善了电荷载流子在界面的注入，另外PEO-DME的掺杂改变了器件内部的电场分布，从而导致电荷载流子的迁移率提高。
2．通过在单层发光活性层中掺杂使用poly(ethylene glycol) dimethyl ether(PEG-DME)，制备了高性能白光磷光PLEDs。根据白光的颜色组成不同，器件的发光活性层中分别掺杂了PVK、OXD-7和两种互补色或者三基色的磷光染料。掺杂的PEG-DME可以有效的增强电子注入和传输，同时平衡电子和空穴的密度。基于两种互补色的白光PLEDs在正向观测亮度为1800cd/m~2时最大的电流效率为17.5cd/A，基于三基色的白光PLEDs在正向观测亮度为3000cd/m~2时最大的电流效率为35.7cd/A，即使发光亮度高达30000cd/m~2时，器件的电流效率仍然可以达到30cd/A以上。器件的高电流效率归因于提高了阴极向聚合物发光活性层的电子注入能力，电荷传输能力和PEG-DME对长波长发光峰的增强作用。另外，器件稳定的电流效率是由于单载流子器件中电荷载流子注入和传输的增强以及激子复合发光区域的移动导致的三重态激子-极化子湮灭和电场导致的三重态激子猝灭减弱。
3．通过溶液法制备银纳米线（AgNW）和AgNW-聚合物复合电极基板，制备了蓝光、绿光和红光磷光PLEDs。基于这类金属纳米结构电极基板的发光器件获得了比传统ITO/玻璃基板上更高的发光效率。蓝光PLEDs在亮度为1400cd/m~2时，电流效率达到21.5cd/A，在发光亮度为450cd/m~2到5500cd/m~2时，器件的效率维持在20-21.5cd/A这个很小的范围之内，即使发光亮度达到10000cd/m~2时，效率仍然可以达到18.5cd/A。根据不同发光颜色，器件的结构略有不同，基于AgNW-聚合物复合电极基板的蓝光、绿光和红光器件的发光效率比基于ITO/玻璃基板的器件高20-50%。三种不同种颜色器件性能的提高归因于AgNW-聚合物复合电极基板具有比ITO/玻璃基板更高的透过率，尤其是在短波长区域和蓝光区域，同时复合电极基板中的AgNW是作为多光子散射中心存在，可以提高基板的出光率。另外，蓝光PLEDs器件可以经过10次到100次的反复弯曲，并且曲率直径只有1.5mm。进过计算，根据器件弯曲的方向不同，发光器件受到的内部压力或者表面张力可以达到5%，并且器件的发光性能变化不大，在器件反复弯曲100次后，电流效率可以保持在初始效率的87%。
4．通过使用AgNW-聚合物复合电极基板制备了高性能磷光白光PLEDs，同时利用复合电极基板提高了白光器件的发光效率和光提取效率。基于两种互补色的白光PLEDs在正向观测亮度为4500cd/m~2时最大的电流效率为20.3cd/A，基于三基色的白光PLEDs在正向观测亮度为4000cd/m~2时最大的电流效率为42.3cd/A，相对于使用ITO/玻璃基板的传统器件，器件的发光效率分别提高了35%和41%。即使在发光亮度提高到10000cd/m~2以上，白光器件的发光效率依然分别保持在20cd/A和40cd/A。白光器件的高电流效率归因于AgNW-聚合物复合电极基板有效提取了传统器件中透明导电电极ITO中被陷阱的40-50%的光波导模式，大大提高了出光效率，另外复合电极基板表面和掩埋在聚合物主体材料内部的AgNW可以通过光散射的方式提取对比器件中玻璃基板中陷阱的光波导模式。此类白光器件同样具有性能优异的弯折性能，在反复弯折测试中，器件张力或者压力为5%的时候，器件的性能几乎不变。
Polymer light-emitting diodes (PLEDs) as the solid lighting and display panel,compared with inorganic LED, liquid crystal display (LCD), have many advantages, e.g.self-emission, fast response, full solid device, super-thin thickness, low cost, especiallyflexible and solution processed. PLEDs are considered as the most ideal and potentiallighting technology in21stcentury. However, now there are also some problems toresolve from large scale commercial application such as low luminous efficiency andhigh fabrication cost due to the imbalance of charge carrier injection and transport andthe cost of commercial transport conductive anode indium-tin oxide (ITO) wasincreasing. Aiming at those problems, some new and systematic works have been doneto focus on the fabrication process to obtain high performance device usingmodification and novel nanostructure electrode to replace the ITO anode with highluminous efficiency for phosphorescent PLEDs.
1. Solution processed blue electrophosphorescent PLEDs have been fabricatedcontaining an oligo(ethylene oxide)(PEO-DME) additive to enhance theelectroluminescence efficiency. The device uses poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) coated on indium tin oxide as the hole injectionelectrode, cesium fluoride/aluminum as the electron injection electrode. The singleemissive layer is a blend of poly(9-vinylcarbazole)(PVK) as the host,bis[(4,6-difluorophenyl)-pyridinato-N,C2](picolinato)Ir(III)(FIrpic) as thephosphorescent dopant, and1,3-bis[(4-tert-butylphenyl)-1,3,4-oxidiazolyl]phenylene(OXD-7) to enhance electron transporting. The addition of an oligo(ethylene oxide) at5-10wt%effectively lowers both the electron and hole injection barriers. The maximumcurrent efficiency obtained was26.5cd/A at an emission brightness of2500cd/m~2. Thehigh performance is due to (i) improved charge carrier injection at the interfaceresulting from specific interfacial interactions between PEO-DME and aluminum,(ii)improved charge carrier transporting ability and high electric field resulting fromPEO-DME doping.
2. White polymer phosphorescent light-emitting diodes (WPLEDs) have been fabricated employing poly(ethylene glycol) dimethyl ether (PEG-DME) blended in thesingle active layer to enhance the emission efficiency. The devices have a simplesandwich architecture of ITO/PEDOT:PSS/emissive layer/CsF/Al. The emissive layeruses a blend of PVK, OXD-7, two or three phosphorescent dopants with complementarycolors. The addition of PEG-DME enhances electron injection, transport, and thebalance of densities of electrons and holes. The measured current efficiency in the frontviewing direction is17.5cd/A at1800cd/cm~2for the two complementary WPLEDs,and35.7cd/A at3000cd/m~2for the three complementary color WPLEDs. The currentefficiencies remain high even at brightness levels up to30,000cd/m~2. The high currentefficiency is ascribed to the improved electron injection ability from the metal cathode,the enhanced charge carrier transport ability and the enhanced red emitting intensity byblending with PEG-DME. Also the low roll-off of the current efficiency was due to thelower triplet-polaron annihilation and the electric field-induced triplet excitonquenching by increased charge carrier transport in unipolar device and movedrecombination zone. The improved charge carrier injection at the interface and theenhanced charge carrier transport were resulted from specific interfacial interactionsbetween PEG-DME and aluminum and higher electric field by blending withPEG-DME.
3. We report the demonstration of blue, green, and red electrophosphorescentPLEDs fabricated on silver nanowire (AgNW) polymer composite electrode. Thecurrent efficiency of the ITO-free blue PLEDs falls in the narrow range of20.0-21.5cd/A in the brightness range of450-5500cd/m~2, and decreases slightly to18.5cd/A at10,000cd/m~2. The devices are20%-50%more efficient than control devices onITO/glass. The current efficiency of the green and red phosphorescent PLEDs was alsoenhanced by20-30%. The improved performance can be attributed to the highertransparency of the AgNW electrode than ITO/glass in the blue region, as well asphoton scattering on the surface of AgNWs in the composite electrode that enhanceslight out-coupling efficiency. The blue PLEDs can be repeatedly bent to1.5mm radiusconcave or convex with calculated strain in the emissive layer to be5%(tensile orcompressive).
4. Phosphorescent WPLEDs have been fabricated employing AgNW-polymercomposite substrate to enhance the light out-coupling and emission efficiency. The current efficiency in the front viewing direction is20.3cd/A for the two complementarycolors devices and42.3cd/A at4000cd/cm~2for the three primary colors devices, theresults are35%and41%higher than that of a conventional WPLEDs used as acomparison, respectively. The high current efficiency is ascribed to the improved lightout-coupling and the waveguided light in ITO and glass substrate could extract in to airfrom light scattering of the AgNW network on the surface and embedded in the polymercomposite. The WPLEDs on the composite substrate are highly flexible and be bent to amaximum5%compressive strain with little decrease on device efficiency.
引文
[1] H. Shirakawa, E. J. Louis, A. G. MacDiarmid, et al. Synthesis of electrically conducting organicpolymers: halogen derivatives of polyacetylene,(CH)x. J. Chem. Soc. Chem. Commun.,1977,(16):578-580
[2] R. F. Service. Getting a charge out of plastics. Science,2000,290(5491):425-427
[3] T. A. Skotherm, R. L. Elsenbaumer, J. R. Reynolds. Handbook of conducting polymers. NewYork: Marcel Dekker,1997,28-29
[4] L. Dai, B. Winkler, L. Dong, et al. Conjugated polymer for light-emitting applications. Adv.Mater.,2001,13(12-13):915-925
[5] J. C. W. Chien. Polyacetylene: chemistry, physics and materials science. New York: AcademicPress Inc,1984,634
[6] L. Dai. Conjugated and fullerene-containing polymers for electronic and photonic applications:advanced syntheses and microlithographic fabrications. J. Macromol. Sci., Rev. Macromol.Chem. Phys.,1999,39(2):273-387
[7] J. H. Burroughes, D. C. C. Bradley, A. R. Brown, et al. Light-emitting diodes based on conjugatedpolymers. Nature,1990,347(6293):539-541
[8] N. C. Greenham, R. H. Friend. Semiconductor Device Physics of Conjugated Polymers. SolidState Phys.,1996,49:1-149
[9] A. Kraft, A. C. Grimsdale, A. B. Holmes. Electroluminescent conjugated polymers seeingpolymers in a new light. Angew. Chem. Int. Ed.,1998,37(4):402-428
[10] R. H. Friend, R. W. Gymer, A. B. Holmes, et al. Electroluminescence in conjugated polymers.Nature,1999,397(6715):121-128
[11] C. W. Tang, S. A. VanSlyke. Organic electroluminescent diodes. Appl. Phys. Lett.,1987,51(12):913-915
[12] J. E. Anthony. Functionalized acenes and heteroacenes for organic electronics. Chem. Rev.,2006,106(12):5028–5048
[13] M. Bendikov, F. Wudl, D. F. Perepichka. Tetrathiafulvalenes, oligoacenenes, and theirbuckminsterfullerene derivatives: the brick and mortar of organic electronics. Chem. Rev.,2004,104(11):4891–4946
[14] A. C. Grimsdale, K. L. Chan, R. E. Martin. Synthesis of light-emitting conjugated polymers forapplications in electroluminescent devices. Chem. Rev.,2009,109(3):897–1091
[15] J. Y. Li, D. Liu. Dendrimers for organic light-emitting diodes. J. Mater. Chem.,2009,19(41):7584–7591
[16] S. C. Lo, P. L. Burn. Development of dendrimers: macromolecules for use in organiclight-emitting diodes and solar cells. Chem. Rev.,2007,107(4):1097–1116
[17] N. Rehmann, D. Hertel, K. Meerholz, et al. Highly efficient solution-processed phosphorescentmultilayer organic light-emitting diodes based on small-molecule hosts. Appl.Phys. Lett.,2007,91(10):103507-1-3
[18] L. D. Hou, L. Duan, J. Qiao, et al. Efficient single layer solution-processed blue-emittingelectrophosphorescent devices based on a small-molecule host. Appl. Phys. Lett.,2008,92(26):263301-1-3
[19] A. P. Kulkarni, C. J. Tonzola, A. Babel, et al. Electron transport materials for organiclight-emitting diodes. Chem. Mater.,2004,16(23):4556–4573
[20] G. Hughes, M. R. Bryce. Electron-transporting materials for organic electroluminescent andelectrophosphorescent devices. J. Mater. Chem.,2005,15(1):94–107
[21] F. Huang, Y.J. Cheng, Y. Zhang, et al. Crosslinkable hole-transporting materials for solutionprocessed polymer light-emitting diodes. J. Mater. Chem.,2008,18(38):4495–4509
[22] F. Huang, H. B. Wu, J. B. Peng, et al. Polyfluorene polyelectrolytes and their precursorsprocessable from environment-friendly solvents (alcohol or water) for PLED applications. Curr.Org. Chem.,2007,11(14):1207–1219
[23] F. Huang, H. B. Wu, Y. Cao. Water/alcohol soluble conjugated polymers as highly efficientelectron transporting/injection layer in optoelectronic devices. Chem. Soc. Rev.,2010,39(7):2500–2521
[24] W. J. Zeng, H. B. Wu, C. Zhang, et al. Polymer light-emitting diodes with cathodes printedfrom conducting Ag paste. Adv. Mater.,2007,19(6):810–814
[25] Z. Zhang, H. Meng. organic light-emitting materials and devices. Boca Raton: Taylor&FrancisGroup,2007,10-12
[26] M. S. Liu, Y. Niu, J. Luo, et al. Material and interface engineering for highly efficient polymerlight emitting diodes. Polym. Rev.,2006,46(1):7-26
[27] P. F. Tian, P. E. Burrows, S. R. Forrest. Photolithographic patterning of vacuum-depositedorganic light emitting devices. App. Phys. Lett.,1997,71(22):3197-3199
[28] S. Reineke, F. Lindner, G. Schwartz, et al. White organic light-emitting diodes with fluorescenttube efficiency. Nature,2009,459(7244):234-238
[29] K. L Jiang, J. P. Wang, Q. Q. Li, et al. Superaligned carbon nanotube arrays, films and yarns: aroad to applications. Adv. Mater.,2011,23(9):1154-1161
[30] S. P. Pang, Y. Hernandez, X. L. Feng, et al. Graphene as transparent electrode material fororganic electronics. Adv. Mater.,2011,23(25):2779-2795
[31] L. B. Hu, H. S. Kim, J. Y. Lee, et al. Scalable coating and properties of transparent, flexible,silver nanowire electrodes. ACS Nano,2010,4(5):2955-2963
[32] K. Yanagi, R. Moriya, Y. Yomogida, et al. Electrochromic carbon electrodes: controllable visiblecolor changes in metallic single-wall carbon nanotubes. Adv. Mater.,2011,23(25):2811-2814
[33] C. Feng, K. Liu, J. S. Wu, et al. Flexible, stretchable, transparent conducting films made fromsuperaligned carbon nanotubes. Adv. Funct. Mater.,2010,20(6):885-891
[34] S. Kim, J. Yim, X. Wang, et al. Spin-and spray-deposited single-walled carbon-nanotubeelectrodes for arganic solar cells. Adv. Funct. Mater.,2010,20(14):2310-2316
[35] M. Musameh, M. R. Notivoli, M. Hickey, et al. Carbon nanotube webs: a novel material forsensor applications. Adv. Mater.,2011,23(7):906-910
[36] J. Wu, M. Agrawal, H. A. Becerril, et al. Organic light-emitting diodes on solution-processedgraphene transparent electrodes. ACS Nano,2010,4(1):43-48
[37] J. M. Yun, J. S. Yeo, J. Kim, et al. Solution-processable reduced graphene oxide as a novelalternative to PEDOT: PSS hole transport layers for highly efficient and stable polymer solarcells. Adv. Mater.,2011,23(42):4923-4928
[38] P. A. Hobson, S. Wedge, J. A. E. Wasey, et al. Surface plasmon mediated emission from organiclight-emitting diodes. Adv. Mater.,2002,14(19):1393-1397
[39] J. Frischeisen, B.J. Scholz, B.J. Arndt, et al. Strategies for light extraction from surfaceplasmons in organic light-emitting diodes. Journal of Photonics for Energy,2011,1:011004
[40] A. E. Strevens, A. Drury, S. M. Lipson, et al. Hybrid light-emitting polymer device fabricatedon a metallic nanowire array. Appl. Phys. Lett.,2005,86(14):143503-1-3
[41] S. A. Choulis, M. K. Mathai, V. E. Choong. Influence of metallic nanoparticles on theperformance of organic electrophosphorescence devices. Appl. Phys. Lett.,2006,88(21):213503-1-3
[42] Y. Xiao, J. P. Yang, P. P. Cheng, et al. Surface plasmon-enhanced electroluminescence in organiclight-emitting diodes incorporating Au nanoparticles. Appl. Phys. Lett.,2012,100(1):013308-1-3
[43] K.Y. Yang, K.C. Choi, C.W. Ahn. Surface plasmon-enhanced energy transfer in an organiclight-emitting device structure. Opt. Express,2009,17(14):11495-11504
[44] J. Frischeisen, Q. Niu, A. Abdellah, et al. Light extraction from surface plasmons andwaveguide modes in an organic light-emitting layer by nanoimprinted gratings. Opt. Express,2011,19(S1): A7-A19
[45] Y. Sun, S. R. Forrest. Organic light emitting devices with enhanced outcoupling via microlensesfabricated by imprint lithography. J. Appl. Phys.,2006,100(7):073106
[46] B. W. D’Andrade, J. J. Brown. Organic light-emitting device luminaire for illuminationapplications. Appl. Phys. Lett.,2006,88(19):192908-1-3
[47] Y. R. Do, Y. C. Kim, Y. W. Song, et al. Enhanced light extraction from organic light-emittingdiodes with2D SiO2/SiNxphotonic crystals. Adv. Mater.,2003,15(14):1214-1218
[48] Y. Sun, S.R. Forrest. Enhanced light out-coupling of organic light-emitting devices usingembedded low-index grids. Nat. Photonics,2008,2(8):483-487
[49] J. H. Jang, M. C. Oh, T. H. Yooh, et al. Polymer grating imbedded organic light emitting diodeswith improved out-coupling efficiency. Appl. Phys. Lett.,2010,97(12):123302-1-3
[50] J. Lee, S. Hofmann, M. Thomschke, et al. Increased and balanced light emission of transparentorganic light-emitting diodes by enhanced microcavity effects. Opt. Lett.,2011,36(15):2931-2933
[51] T. Yamasaki, K. Sumioka, T. Tsutsui. Organic light-emitting device with an ordered monolayerof silica microspheres as a scattering medium. Appl. Phys. Lett.,2000,76(10):1243-1245
[52] W.L. Barnes, A. Dereux, T.W. Ebbesen. Surface plasmon subwavelength optics. Nature,2003,424(6950):824-830
[53] S.Y. Hsu, M.C. Lee, K.L. Lee, et al. Extraction enhancement in organic light emitting devicesby using metallic nanowire arrays. Appl. Phys. Lett.,2008,92(1):013303-1-3
[54] M.G. Kang, L.J. Guo. Nanoimprinted semitransparent metal electrodes and their application inorganic light-emitting Diodes. Adv. Mater.,2007,19(10):1391-1396
[55] X.Y. Zeng, Q.K. Zhang, R.M. Yu, et al. A new transparent conductor: silver nanowire filmburied at the surface of a transparent polymer. Adv. Mater.,2010,22(40):4484-4488
[56] Z. B Yu, Q. W. Zhang, L. Li, et al. Highly flexible silver nanowire electrodes for shape memorypolymer light-emitting diodes. Adv. Mater.,2011,23(5):664-668
[57] T. Earmme, E. Ahmed, and S. A. Jenekhe. Solution-processed highly efficient blue phosphor-rescent polymer light-emitting diodes enabled by a new electron transport material. Adv.Mater.,2010,22(42):4744-4748
[58] M. A. Baldo, D. F. O’Brien, Y. You, et al. Highly efficient phosphorescent emission fromorganic electroluminescent devices. Nature.,1998,395(6698):151-154
[59] J. Liu, and Q. Pei. Electrophosphorescent polymers for high-efficiency light-emitting diodes.Curr. Org. Chem.,2010,14(18):2133-2144
[60] F. Huang, P. I. Shih, M. S. Liu, et al. Lithium salt doped conjugated polymers as electrontransporting materials for highly efficient blue polymer light-emitting diodes. Appl. Phys. Lett.,2008,93(24):243302-1-3
[61] X. H. Yang, F. Jaiser, S. Klinger, et al. Blue polymer electrophosphorescent devices withdifferent electron-transporting oxadiazoles. Appl. Phys. Lett.,2006,88(2):021107-1-3
[62] M. Mathai, V. Choong, S. Choulis, et al. Highly efficient solution processed blue organicelectrophosphorescence with14lm/W luminous efficacy. Appl. Phys. Lett.,2006,88(24):243512-1-3
[63] P. Sigaud, J.-N. Chazalviel, and F. Ozanam. Barrier lowering and reorientation of dipolesgrafted at indium-tin-oxide/polymer interfaces. J. Appl. Phys.,2002,92(2):992-996
[64] F. Chen, S. Chien, and Y. Chen. Single-layer triplet white polymer light-emitting diodesincorporating polymer oxides: Effect of charge trapping at phosphorescent dopants. Appl. Phys.Lett.,2009,94(4):043306-1-3
[65] T. Guo, F. Yang, Z. Tsai, et al. High-performance polymer light-emitting diodes utilizingmodified Al cathode. Appl. Phys. Lett.,2005,87(1):013504-1-3
[66] Z. Yu, M. Sun, and Q. Pei. Electrochemical formation of stable p-i-n junction in conjugatedpolymer thin films. J. Phys. Chem. B.,2009,113(25):8481-8486
[67] F. Chen, S. Chien, and S. Lee. High-performance single-layer polymer electrophosphorescentdevice with polymer oxides. Electrochem. Solid-State Lett.,2008,11(6): J50-J53
[68] Z. Yu, M. Wang, G. Lei, et al. Stabilizing the dynamic p-i-n junction in polymer light-emittingelectrochemical cells. J. Phys, Chem. Lett.,2011,2(5):367-372
[69] R. H. Fowler, F. R. S, and L. W. Nordheim. Electron emissioin in intense electric fields. Proc RSoc.,1928,119(781):173
[70] X. Y. Deng, W. M. Lau, K. Y. Wong, et al. High efficiency low operating voltage polymerlight-emitting diodes with aluminum cathode. Appl. Phys. Lett.,2004,84(18):3522-3524
[71] Y. Niu, H. Ma, Q. Xu, et al. High-efficiency light-emitting diodes using neutral surfactants andaluminum cathode. Appl. Phys. Lett.,2005,86(8):083504-1-3
[72] F. Huang, Y. Zhang, M. S. Liu, et al. Electron-rich alcohol-soluble neutral conjugated polymersas highly efficient electron-injecting materials for polymer light-emitting diodes. Adv. Func.Mater.,2009,19(15):2457-2466
[73] H. B. Wu, F. Huang, Y. Q. Mo, et al. Efficient electron injection from a bilayer cathodeconsisting of aluminum and alcohol-/water-soluble conjugated polymers. Adv. Mater.,2004,16(20):1826-1830
[74] W. L. Ma, P. K. Iyer, X. Gong, et al. Water/methanol-soluble conjugated copolymer as anelectron-transport layer in polymer light-emitting diodes. Adv. Mater.,2005,17(3):274-277
[75] R. Q. Yang, H. B. Wu, Y. Cao, et al. Control of cationic conjugated polymer performance inlight emitting diodes by choice of counterion. J. Am. Chem. Soc.,2006,128(45):14422-14423
[76] J. Kido, M. Kimura, and K. Nagai. Multilayer white light-emitting organic electroluminescentdevice. Science.,1995,267(5202):1332-1334
[77] B. W. D’Andrade, S. R. Forrest. White organic light-emitting devices for solid-state lighting.Adv. Mater.,2004,16(18):1585-1595
[78] K. T. Kamtekar, A. P. Monkman, and M. R. Bryce. Recent advances in white organiclight-emitting materials and devices (WOLEDs). Adv. Mater.,2010,22(5):572-582
[79] M. C. Gather, A. K hnen, and K. Meerholz. White organic light-emitting diodes. Adv. Mater.,2011,23(2):233-248
[80] L. Xiao, Z. Chen, B. Qu, et al. Recent progresses on materials for electrophosphorescentorganic light-emitting devices. Adv. Mater.,2011,23(8):926-952
[81] Q. Xu, H. M. Duong, F. Wudl, et al. Efficient single-layer “twistacene”-doped polymer whitelight-emitting diodes. Appl. Phys. Lett.,2004,85(16):3357-3359
[82] Y. R. Sun and S. R. Forrest. High-efficiency white organic light emitting devices with threeseparate phosphorescent emission layers. Appl. Phys. Lett.,2007,91(26):263503-1-3
[83] X. Gong, W. Ma, J. C. Ostrowski, et al. White electrophosphorescence from semiconductingpolymer blends. Adv. Mater.,2004,16(7):615-619
[84] X. Gong, S. Wang, D. Moses, et al. Multilayer polymer light-emitting diodes: white-lightemission with high efficiency. Adv. Mater.,2005,17(17):2053-2058
[85] J. H. Jou, M. C. Sun, H. H. Chou, et al. Efficient pure-white organic light-emitting diodes with asolution-processed, binary-host employing single emission layer. Appl. Phys. Lett.,2006,88(14):141101-1-3
[86] P. I. Shih, Y. H. Tseng, F. I. Wu, et al. Stable and efficient white electroluminescent devicesbased on a single emitting layer of polymer blends. Adv. Funct. Mater.,2006,16(12):1582-1589
[87] Y. H. Xu, J. B. Peng, J. X. Jiang, et al. Efficient white-light-emitting diodes based on polymercodoped with two phosphorescent dyes. Appl. Phys. Lett.,2005,87(19):193502-1-3
[88] H. Wu, J. Zou, F. Liu, et al. Efficient single active layer electrophosphorescent white polymerlight-emitting diodes. Adv. Mater.,2008,20(4):696-702
[89] F. Huang, P. Shih, C. F. Shu, et al. Highly efficient polymer white-light-emitting diodes basedon lithium salts doped electron transporting layer. Adv. Mater.,2009,21(3):361-365
[90] B. W. D’Andrade, M. E. Thompson, and S. R. Forrest. Controlling exciton diffusion inMultilayer white phosphorescent organic light emitting devices. Adv. Mater.,2002,14(2):147-151
[91] Y. Sun, N. C. Giebink, and H. Kanno. Management of singlet and triplet excitons for efficientwhite organic light-emitting devices. Nature.,2006,440(7086):908-912
[92] G. Schwartz, S. Reineke, T. C. Rosenow, et al. Triplet harvesting in hybrid white organiclight-emitting diodes. Adv. Funct. Mater.,2009,19(9):1319-1333
[93] B. W. D’Andrade, R. J. Holmes, and S. R. Forrest. Efficient organic electrophosphorescentwhite-light-emitting device with a triple doped emissive layer. Adv. Mater.,2004,16(7):624-628
[94] M. Sun, C. Zhong, F. Li, et al. A fluorine-oxadiazole copolymer for white light-emittingelectrochemical cells. Macromolecules.,2010,43(4):1714-1718
[95] E. L. Williams, K. Haavisto, J. Li, et al. Excimer-based white phosphorescent organic light-emitting diodes with nearly100%internal quantum efficiency. Adv. Mater.,2007,19(2):197-202
[96] J. X. Jiang, Y. H. Xu, W. Yang, et al. High-efficiency white-light-emitting devices from asingle polymer by mixing singlet and triplet emission. Adv. Mater.,2006,18(13):1769-1773
[97] J. Liu, Q. G. Zhou, Y. X. Cheng, et al. White electroluminescence from a single-polymersystem with simultaneous two-color emission: polyfluorene as the blue host and a2,1,3-benzothia-diazole derivative as the orange dopant. Adv. Funct. Mater.,2006,16(7):957-965
[98] H. J. Peng, X. L. Zhu, J. X. Sun, et al. Efficiency improvement of phosphorescent organiclight-emitting diodes using semitransparent Ag as anode. Appl. Phys. Lett.,2006,88(3):033509-1-3
[99] R. J. Holmes, S. R. Forrest, Y. J. Tung, et al. Blue organic electrophosphorescence usingexothermic host–guest energy transfer. Appl. Phys. Lett.,2003,82(15):2422-2424
[100] L. Zeng, T. Y. Lee, P. Merkel, et al. A new class of non-conjugated bipolar hybrid hosts forphosphorescent organic light-emitting diodes. J. Chem. Mater.,2009,19(46):8772-8781
[101] C. Yang, C. Tai, and I. Sun. Synthesis of a high-efficiency red phosphorescent emitter fororganic light-emitting diodes. J. Chem. Mater.,2004,14(6):947-950
[102] J. Wang, Y. D. Jiang, J. S. Yu, et al. Low operating voltage bright organic light-emitting diodeusing iridium complex doped in4,4′-bis[N-1-napthyl-N-phenyl-amino] biphenyl. Appl. Phys.Lett.,2007,91(13):131105-1-3
[103] J. Wang, J. Yu, L. Li, et al. Low roll-off power efficiency organic light-emitting diodesconsisted of nondoped ultrathin phosphorescent layer. Appl. Phys. Lett.,2008,92(13):133308-1-3
[104] M. A. Baldo, C. Adachi, and S. R. Forrest. Transient analysis of organic electrophosphoresc-ence. II. Transient analysis of triplet-triplet annihilation. Phys. Rev. B.,2000,62(16):10967-10977
[105] S. Reineke, K. Walzer, and K. Leo. Triplet-exciton quenching in organic phosphorescentlight-emitting diodes with Ir-based emitters. Phys. Rev. B.,2007,75(12):125328-1-13
[106] J. Kalinowski, W. Stampor, and J. Mezyk. Quenching effects in organic electrophosphores-cence. Phys. Rev. B.,2002,66(23):235321-1-15
[107] L. Li, J. Liu, Z. Yu, et al. Highly efficient blue phosphorescent polymer light-emitting diodesby using interfacial modification. Appl. Phys. Lett.,2011,98(20):201110-1-3
[108] X. Gong, S. H. Lim, J. C. Ostrowski, et al. Phosphorescence from iridium complexes dopedinto polymer blends. J. Appl. Phys.,2004,95(3):948-953
[109] C. Adachi, M. A. Baldo, and S. R. Forrest. Electroluminescence mechanisms in organic lightemitting devices employing a europium chelate doped in a wide energy gap bipolarconducting host. J. Appl. Phys.,2000,87(11):8049-8055
[110] P. A. Lane, L. C. Palilis, D. F. O’Brien, et al. Origin of electrophosphorescence from a dopedpolymer light emitting diode. Phys. Rev. B.,2001,63(23):235206-1-8
[111] B. Hu, F. E. Karasz, Blue, green, red, and white electroluminescence from multichromophorepolymer blends. J. Appl. Phys.,2003,93(4):1995-2001
[112] M. Gather, R. Alle, H. Becker, et al. On the Origin of the Color Shift in White-EmittingOLEDs. Adv. Mater.,2007,19(24):4460-4465
[113] G. Gustafsson, Y. Cao, G. M. Treacy, et al. A. J. Heeger, Flexible light-emitting diodes madefrom soluble conducting polymers. Nature,1992,357:477-479
[114] G. Gu, P. E. Burrows, S. Venkatesh, et al. Vacuum-deposited, nonpolymeric flexible organiclight-emitting devices. Opt. Lett.,1997,22(3):172-174.
[115] T. R. Hebner, C. C. Wu, D. Marcy, et al. Ink-jet printing of doped polymers for organic lightemitting devices. Appl. Phys. Lett.,1998,72(5):519-511.
[116] H. Yang, Z. Wang, S. Madakuni, et al. Highly efficient excimer-based white phosphorescentdevices with improved power efficiency and color rendering index. Appl. Phys. Lett.,2008,93(19):193305.
[117] Z. Yu, L. Hu, Z. Liu, et al. Fully bendable polymer light emitting devices with carbonnanotubes as cathode and anode. Appl. Phys. Lett.,2009,95(20):203304.
[118] M. A. Ibrahim, H. K. Roth, M. Schroedner, et al. The influence of the optoelectronicproperties of poly(3-alkylthiophenes) on the device parameters in flexible polymer solar cells.Org. Electron.,2005,6(2):65-77.
[119] R. Paetzold, K. Heuser, D. Henseler, et al. Performance of flexible polymeric light-emittingdiodes under bending conditions. Appl. Phys. Lett.,2003,82(19):3342-3344.
[120] W. A. Gazotti, G. C. Miceli, A. Geri, et al. An all-plastic and flexible electrochromic devicebased on elastomeric blends. Adv. Mater.,1998,10(18):1522-1525.
[121] Y. Yang, Q. Huang, A. W. Metz, et al. High-performance organic light-emitting diodes usingITO anodes grown on plastic by room-temperature ion-assisted deposition. Adv. Mater.,2004,16(4):321-324.
[122] J. Y. Lee, S. T. Connor, Y. Cui, et al. Solution-processed metal nanowire mesh transparentelectrodes. Nano Lett.,2008,8(2):689-692.
[123] S. De, T. M. Higgins, P. E. Lyons, et al. Silver nanowire networks as flexible, transparent,conducting films: extremely high DC to optical conductivity ratios. ACS Nano,2009,3(7):1767-1774.
[124] W. Gaynor, J. Y. Lee, Fully Solution-processed inverted polymer solar cells with laminatednanowire electrodes, P. Peuman. ACS Nano,2010,4(1):30-34.
[125] L. Hu, D. S. Hecht, G. Gruner, Percolation in transparent and conducting carbon nanotubenetworks. Nano Lett.,2004,4(12):2513-2517
[126] J. Li, L. Hu, L. Wang, et al. Organic light-emitting diodes having carbon nanotube anodes.Nano Lett.,2006,6(11):2472-2477.
[127] W. Yuan, L. B. Hu, Z. B. Yu, et al. Fault-tolerant dielectric elastomer actuators usingsingle-walled carbon nanotube electrodes. Adv. Mater.,2008,20(3):621-625.
[128] D. Azulai, T. Belenkova, H. Gilon, et al. Transparent metal nanowire thin films prepared inmesostructured templates, G. Markovich. Nano Lett.,2009,9(12):4246-4249.
[129] Z. Hou, C. K. Tsung, W. Huang, et al. Sub-two nanometer single crystal Au nanowires. NanoLett.,2008,8(7):2041-2044.
[130] X. Lu, M. S. Yavuz, H. Y. Tuan, et al. Ultrathin gold nanowires can be obtained by reducingpolymeric strands of oleylamine AuCl complexes formed via aurophilic interaction. J. Am.Chem. Soc.,2008,130(28):8900-8901.
[131] C. Wang, Y. Hu, C. M. Lieber, et al. Ultrathin Au nanowires and their transport properties. J.Am. Chem. Soc.,2008,130(28):8902-8903.
[132] Z. Yu, X. Niu, Z. Liu, et al. Intrinsically stretchable polymer light-emitting devices usingcarbon nanotube-polymer composite electrodes. Adv. Mater.,2011,23(34):3989-3994.
[133] Y. G. Sun, B. Gates, B. Mayers, et al. Crystalline silver nanowires by soft solution processing.Nano Lett.,2002,2(2):165-168.
[134] K. K. Kim, S. D. Lee, H. Kim, et al. Enhanced light extraction efficiency of GaN-basedlight-emitting diodes with ZnO nanorod arrays grown using aqueous solution. Appl. Phys.Lett.,2009,94(7):071118.
[135] X. Yang, D. Neher, D. Hertel, et al. Highly efficient single-layer polymerelectrophosphorescent devices. Adv. Mater.,2004,16(2):161-166.
[136] F. I. Wu, H. J. Su, C. F. Shu, et al. Tuning the emission and morphology of cyclometalatediridium complexes and their applications to organic light-emitting diodes. J. Mater. Chem.,2005,15(10):1035-1042.
[137] M. Suzuki, S. Tokito, F. Sato, T. Igarashi, K. Kondo, et al. Highly efficient polymerlight-emitting devices using ambipolar phosphorescent polymers. Appl. Phys. Lett.,2005,86(10):103507.
[138] Z. Wu, L. Wang, G. Lei, et al. Investigation of the spectra of phosphorescent organiclight-emitting devices in relation to emission zone. J. Appl. Phys.,2005,97(10):103105.
[139] J. Zou, H. Wu, C. Lam, et al. Simultaneous optimization of charge-carrier balance andluminous efficacy in highly efficient white polymer light-emitting devices. Adv. Mater.,2011,23(26):2976-2980
[140] C. Adachi, M. A. Baldo, M. E. Thompson, et al. Nearly100%internal phosphorescenceefficiency in an organic light-emitting device. J. Appl. Phys.,2001,90(10):5048-5051
[141] A. Chutinan, K. Ishihara, T. Asano, et al. Theoretical analysis on light-extraction efficiency oforganic light-emitting diodes using FDTD and mode-expansion methods. Org. Electron.,2005,6(1):3-9
[142] V. Bulovic, V. B. Khalfin, G. Yu, et al. Weak microcavity effects in organic light-emittingdevices. Phys. Rev. B,1998,58(7):3730-3740
[143] K. Saxena, V. K. Jain, D. Mehta. A review on the light extraction techniques in organicelectroluminescent devices. Opt. Mater.,2009,32(1):221-233
[144] J. Kim, P. K. H. Ho, N. C. Greenham, et al. Electroluminescence emission pattern of organiclight-emitting diodes: Implications for device efficiency calculations. J. Appl. Phys.,2000,88(2):1073-1081
[145] M. H. Lu, J. C. Sturn, External coupling efficiency in planar organic light-emitting devices.Appl. Phys. Lett.,2001,78(13):1927-1929
[146] T. Nakamura, N. Tsutsumi, N. Juni, et al. Thin-film waveguiding mode light extraction inorganic electroluminescent device using high refractive index substrate. J. Appl. Phys.,2005,97(5),054505
[147] Y. H. Cheng, J. L. Wu, C. H. Cheng. Enhanced light outcoupling in a thin film by texturingmeshed surfaces. Appl. Phys. Lett.,2007,90(9):091102
[148] J. M. Ziebarth, A. K. Saafir, S. Fan, et al. Extracting light from polymer light-emitting diodesusing stamped bragg gratings. Adv. Funct. Mater.,2004,14(5):451-456
[149] J. J. Shiang, T. J. Faircloth, A. R. Duggal, Experimental demonstration of increased organiclight emitting device output via volumetric light scattering. J. Appl. Phys.,2004,95(5):2889-2895
[150] F. Li, X. Li, J. Zhang, et al. Enhanced light extraction from organic light-emitting devices byusing microcontact printed silica colloidal crystals. Org. Electron.,2007,8(5):635-639
[151] S. Moller, S. R. Forrest, Improved light out-coupling in organic light emitting diodesemploying ordered microlens arrays. J. Appl. Phys.,2002,91(5):3324-3327
[152] M. Wei, I. Su, Method to evaluate the enhancement of luminance efficiency in planar OLEDlight emitting devices for microlens array. Opt. Exp.,2004,12(23):5777-5782
[153] T. Shiga, H. Fujikawa, Y. Taga, Design of multiwavelength resonant cavities for white organiclight-emitting diodes. J. Appl. Phys.,2003,93(1):19-22
[154] T. Cho, C. Lin, C. Wu, Microcavity two-unit tandem organic light-emitting devices having ahigh efficiency. Appl. Phys. Lett.,2006,88(11):111106
[155] Y. R. Do, Y. Kim, Y. Song, et al. Enhanced light extraction efficiency from organic lightemitting diodes by insertion of a two-dimensional photonic crystal structure. J. Appl. Phys.,2004,96(12):7629-7636
[156] C. Liu, V. Kamaev, Z. V. Vardeny, Efficiency enhancement of an organic light-emitting diodewith a cathode forming two-dimensional periodic hole array. Appl. Phys. Lett.,2005,86(14):143501
[157] S. Noda, M. Fujita, T. Asano, Spontaneous-emission control by photonic crystals andnanocavities. Nat. Photonics,20071(8):449-458
[158] E. Ozbay, Plasmonics: merging photonics and electronics at nanoscale dimensions. Science,2006,311(5758):189-193
[159] Y. Bao, B. Zhang, Z. Wu, et al. Surface-plasmon-enhanced transmission through metallic filmperforated with fractal-featured aperture array. Appl. Phys. Lett.,2007,90(25):251914
[160] H. J. Peng, Y. L. Ho, X. J. Yu, et al. Enhanced coupling of light from organic light emittingdiodes using nanoporous films. J. Appl. Phys.,2004,96(3):1649-1654
[161] M. Agarwal, Y. Sun, S. R. Forrest, et al. Enhanced outcoupling from organic light-emittingdiodes using aperiodic dielectric mirrors. Appl. Phys. Lett.,2007,90(24):241112
[162] T. Tsutsui, M. Yahiro, H. Yokogawa, et al. Doubling coupling-out efficiency in organiclight-emitting devices using a thin silica aerogel layer. Adv. Mater.,2001,13(15):1149-1152
[163] W. Koo, S. Jeong, F. Araoka, et al. Light extraction from organic light-emitting diodesenhanced by spontaneously formed buckles. Nat. Photonics,2010,4(4):222-226
[2] R. F. Service. Getting a charge out of plastics. Science,2000,290(5491):425-427
[3] T. A. Skotherm, R. L. Elsenbaumer, J. R. Reynolds. Handbook of conducting polymers. NewYork: Marcel Dekker,1997,28-29
[4] L. Dai, B. Winkler, L. Dong, et al. Conjugated polymer for light-emitting applications. Adv.Mater.,2001,13(12-13):915-925
[5] J. C. W. Chien. Polyacetylene: chemistry, physics and materials science. New York: AcademicPress Inc,1984,634
[6] L. Dai. Conjugated and fullerene-containing polymers for electronic and photonic applications:advanced syntheses and microlithographic fabrications. J. Macromol. Sci., Rev. Macromol.Chem. Phys.,1999,39(2):273-387
[7] J. H. Burroughes, D. C. C. Bradley, A. R. Brown, et al. Light-emitting diodes based on conjugatedpolymers. Nature,1990,347(6293):539-541
[8] N. C. Greenham, R. H. Friend. Semiconductor Device Physics of Conjugated Polymers. SolidState Phys.,1996,49:1-149
[9] A. Kraft, A. C. Grimsdale, A. B. Holmes. Electroluminescent conjugated polymers seeingpolymers in a new light. Angew. Chem. Int. Ed.,1998,37(4):402-428
[10] R. H. Friend, R. W. Gymer, A. B. Holmes, et al. Electroluminescence in conjugated polymers.Nature,1999,397(6715):121-128
[11] C. W. Tang, S. A. VanSlyke. Organic electroluminescent diodes. Appl. Phys. Lett.,1987,51(12):913-915
[12] J. E. Anthony. Functionalized acenes and heteroacenes for organic electronics. Chem. Rev.,2006,106(12):5028–5048
[13] M. Bendikov, F. Wudl, D. F. Perepichka. Tetrathiafulvalenes, oligoacenenes, and theirbuckminsterfullerene derivatives: the brick and mortar of organic electronics. Chem. Rev.,2004,104(11):4891–4946
[14] A. C. Grimsdale, K. L. Chan, R. E. Martin. Synthesis of light-emitting conjugated polymers forapplications in electroluminescent devices. Chem. Rev.,2009,109(3):897–1091
[15] J. Y. Li, D. Liu. Dendrimers for organic light-emitting diodes. J. Mater. Chem.,2009,19(41):7584–7591
[16] S. C. Lo, P. L. Burn. Development of dendrimers: macromolecules for use in organiclight-emitting diodes and solar cells. Chem. Rev.,2007,107(4):1097–1116
[17] N. Rehmann, D. Hertel, K. Meerholz, et al. Highly efficient solution-processed phosphorescentmultilayer organic light-emitting diodes based on small-molecule hosts. Appl.Phys. Lett.,2007,91(10):103507-1-3
[18] L. D. Hou, L. Duan, J. Qiao, et al. Efficient single layer solution-processed blue-emittingelectrophosphorescent devices based on a small-molecule host. Appl. Phys. Lett.,2008,92(26):263301-1-3
[19] A. P. Kulkarni, C. J. Tonzola, A. Babel, et al. Electron transport materials for organiclight-emitting diodes. Chem. Mater.,2004,16(23):4556–4573
[20] G. Hughes, M. R. Bryce. Electron-transporting materials for organic electroluminescent andelectrophosphorescent devices. J. Mater. Chem.,2005,15(1):94–107
[21] F. Huang, Y.J. Cheng, Y. Zhang, et al. Crosslinkable hole-transporting materials for solutionprocessed polymer light-emitting diodes. J. Mater. Chem.,2008,18(38):4495–4509
[22] F. Huang, H. B. Wu, J. B. Peng, et al. Polyfluorene polyelectrolytes and their precursorsprocessable from environment-friendly solvents (alcohol or water) for PLED applications. Curr.Org. Chem.,2007,11(14):1207–1219
[23] F. Huang, H. B. Wu, Y. Cao. Water/alcohol soluble conjugated polymers as highly efficientelectron transporting/injection layer in optoelectronic devices. Chem. Soc. Rev.,2010,39(7):2500–2521
[24] W. J. Zeng, H. B. Wu, C. Zhang, et al. Polymer light-emitting diodes with cathodes printedfrom conducting Ag paste. Adv. Mater.,2007,19(6):810–814
[25] Z. Zhang, H. Meng. organic light-emitting materials and devices. Boca Raton: Taylor&FrancisGroup,2007,10-12
[26] M. S. Liu, Y. Niu, J. Luo, et al. Material and interface engineering for highly efficient polymerlight emitting diodes. Polym. Rev.,2006,46(1):7-26
[27] P. F. Tian, P. E. Burrows, S. R. Forrest. Photolithographic patterning of vacuum-depositedorganic light emitting devices. App. Phys. Lett.,1997,71(22):3197-3199
[28] S. Reineke, F. Lindner, G. Schwartz, et al. White organic light-emitting diodes with fluorescenttube efficiency. Nature,2009,459(7244):234-238
[29] K. L Jiang, J. P. Wang, Q. Q. Li, et al. Superaligned carbon nanotube arrays, films and yarns: aroad to applications. Adv. Mater.,2011,23(9):1154-1161
[30] S. P. Pang, Y. Hernandez, X. L. Feng, et al. Graphene as transparent electrode material fororganic electronics. Adv. Mater.,2011,23(25):2779-2795
[31] L. B. Hu, H. S. Kim, J. Y. Lee, et al. Scalable coating and properties of transparent, flexible,silver nanowire electrodes. ACS Nano,2010,4(5):2955-2963
[32] K. Yanagi, R. Moriya, Y. Yomogida, et al. Electrochromic carbon electrodes: controllable visiblecolor changes in metallic single-wall carbon nanotubes. Adv. Mater.,2011,23(25):2811-2814
[33] C. Feng, K. Liu, J. S. Wu, et al. Flexible, stretchable, transparent conducting films made fromsuperaligned carbon nanotubes. Adv. Funct. Mater.,2010,20(6):885-891
[34] S. Kim, J. Yim, X. Wang, et al. Spin-and spray-deposited single-walled carbon-nanotubeelectrodes for arganic solar cells. Adv. Funct. Mater.,2010,20(14):2310-2316
[35] M. Musameh, M. R. Notivoli, M. Hickey, et al. Carbon nanotube webs: a novel material forsensor applications. Adv. Mater.,2011,23(7):906-910
[36] J. Wu, M. Agrawal, H. A. Becerril, et al. Organic light-emitting diodes on solution-processedgraphene transparent electrodes. ACS Nano,2010,4(1):43-48
[37] J. M. Yun, J. S. Yeo, J. Kim, et al. Solution-processable reduced graphene oxide as a novelalternative to PEDOT: PSS hole transport layers for highly efficient and stable polymer solarcells. Adv. Mater.,2011,23(42):4923-4928
[38] P. A. Hobson, S. Wedge, J. A. E. Wasey, et al. Surface plasmon mediated emission from organiclight-emitting diodes. Adv. Mater.,2002,14(19):1393-1397
[39] J. Frischeisen, B.J. Scholz, B.J. Arndt, et al. Strategies for light extraction from surfaceplasmons in organic light-emitting diodes. Journal of Photonics for Energy,2011,1:011004
[40] A. E. Strevens, A. Drury, S. M. Lipson, et al. Hybrid light-emitting polymer device fabricatedon a metallic nanowire array. Appl. Phys. Lett.,2005,86(14):143503-1-3
[41] S. A. Choulis, M. K. Mathai, V. E. Choong. Influence of metallic nanoparticles on theperformance of organic electrophosphorescence devices. Appl. Phys. Lett.,2006,88(21):213503-1-3
[42] Y. Xiao, J. P. Yang, P. P. Cheng, et al. Surface plasmon-enhanced electroluminescence in organiclight-emitting diodes incorporating Au nanoparticles. Appl. Phys. Lett.,2012,100(1):013308-1-3
[43] K.Y. Yang, K.C. Choi, C.W. Ahn. Surface plasmon-enhanced energy transfer in an organiclight-emitting device structure. Opt. Express,2009,17(14):11495-11504
[44] J. Frischeisen, Q. Niu, A. Abdellah, et al. Light extraction from surface plasmons andwaveguide modes in an organic light-emitting layer by nanoimprinted gratings. Opt. Express,2011,19(S1): A7-A19
[45] Y. Sun, S. R. Forrest. Organic light emitting devices with enhanced outcoupling via microlensesfabricated by imprint lithography. J. Appl. Phys.,2006,100(7):073106
[46] B. W. D’Andrade, J. J. Brown. Organic light-emitting device luminaire for illuminationapplications. Appl. Phys. Lett.,2006,88(19):192908-1-3
[47] Y. R. Do, Y. C. Kim, Y. W. Song, et al. Enhanced light extraction from organic light-emittingdiodes with2D SiO2/SiNxphotonic crystals. Adv. Mater.,2003,15(14):1214-1218
[48] Y. Sun, S.R. Forrest. Enhanced light out-coupling of organic light-emitting devices usingembedded low-index grids. Nat. Photonics,2008,2(8):483-487
[49] J. H. Jang, M. C. Oh, T. H. Yooh, et al. Polymer grating imbedded organic light emitting diodeswith improved out-coupling efficiency. Appl. Phys. Lett.,2010,97(12):123302-1-3
[50] J. Lee, S. Hofmann, M. Thomschke, et al. Increased and balanced light emission of transparentorganic light-emitting diodes by enhanced microcavity effects. Opt. Lett.,2011,36(15):2931-2933
[51] T. Yamasaki, K. Sumioka, T. Tsutsui. Organic light-emitting device with an ordered monolayerof silica microspheres as a scattering medium. Appl. Phys. Lett.,2000,76(10):1243-1245
[52] W.L. Barnes, A. Dereux, T.W. Ebbesen. Surface plasmon subwavelength optics. Nature,2003,424(6950):824-830
[53] S.Y. Hsu, M.C. Lee, K.L. Lee, et al. Extraction enhancement in organic light emitting devicesby using metallic nanowire arrays. Appl. Phys. Lett.,2008,92(1):013303-1-3
[54] M.G. Kang, L.J. Guo. Nanoimprinted semitransparent metal electrodes and their application inorganic light-emitting Diodes. Adv. Mater.,2007,19(10):1391-1396
[55] X.Y. Zeng, Q.K. Zhang, R.M. Yu, et al. A new transparent conductor: silver nanowire filmburied at the surface of a transparent polymer. Adv. Mater.,2010,22(40):4484-4488
[56] Z. B Yu, Q. W. Zhang, L. Li, et al. Highly flexible silver nanowire electrodes for shape memorypolymer light-emitting diodes. Adv. Mater.,2011,23(5):664-668
[57] T. Earmme, E. Ahmed, and S. A. Jenekhe. Solution-processed highly efficient blue phosphor-rescent polymer light-emitting diodes enabled by a new electron transport material. Adv.Mater.,2010,22(42):4744-4748
[58] M. A. Baldo, D. F. O’Brien, Y. You, et al. Highly efficient phosphorescent emission fromorganic electroluminescent devices. Nature.,1998,395(6698):151-154
[59] J. Liu, and Q. Pei. Electrophosphorescent polymers for high-efficiency light-emitting diodes.Curr. Org. Chem.,2010,14(18):2133-2144
[60] F. Huang, P. I. Shih, M. S. Liu, et al. Lithium salt doped conjugated polymers as electrontransporting materials for highly efficient blue polymer light-emitting diodes. Appl. Phys. Lett.,2008,93(24):243302-1-3
[61] X. H. Yang, F. Jaiser, S. Klinger, et al. Blue polymer electrophosphorescent devices withdifferent electron-transporting oxadiazoles. Appl. Phys. Lett.,2006,88(2):021107-1-3
[62] M. Mathai, V. Choong, S. Choulis, et al. Highly efficient solution processed blue organicelectrophosphorescence with14lm/W luminous efficacy. Appl. Phys. Lett.,2006,88(24):243512-1-3
[63] P. Sigaud, J.-N. Chazalviel, and F. Ozanam. Barrier lowering and reorientation of dipolesgrafted at indium-tin-oxide/polymer interfaces. J. Appl. Phys.,2002,92(2):992-996
[64] F. Chen, S. Chien, and Y. Chen. Single-layer triplet white polymer light-emitting diodesincorporating polymer oxides: Effect of charge trapping at phosphorescent dopants. Appl. Phys.Lett.,2009,94(4):043306-1-3
[65] T. Guo, F. Yang, Z. Tsai, et al. High-performance polymer light-emitting diodes utilizingmodified Al cathode. Appl. Phys. Lett.,2005,87(1):013504-1-3
[66] Z. Yu, M. Sun, and Q. Pei. Electrochemical formation of stable p-i-n junction in conjugatedpolymer thin films. J. Phys. Chem. B.,2009,113(25):8481-8486
[67] F. Chen, S. Chien, and S. Lee. High-performance single-layer polymer electrophosphorescentdevice with polymer oxides. Electrochem. Solid-State Lett.,2008,11(6): J50-J53
[68] Z. Yu, M. Wang, G. Lei, et al. Stabilizing the dynamic p-i-n junction in polymer light-emittingelectrochemical cells. J. Phys, Chem. Lett.,2011,2(5):367-372
[69] R. H. Fowler, F. R. S, and L. W. Nordheim. Electron emissioin in intense electric fields. Proc RSoc.,1928,119(781):173
[70] X. Y. Deng, W. M. Lau, K. Y. Wong, et al. High efficiency low operating voltage polymerlight-emitting diodes with aluminum cathode. Appl. Phys. Lett.,2004,84(18):3522-3524
[71] Y. Niu, H. Ma, Q. Xu, et al. High-efficiency light-emitting diodes using neutral surfactants andaluminum cathode. Appl. Phys. Lett.,2005,86(8):083504-1-3
[72] F. Huang, Y. Zhang, M. S. Liu, et al. Electron-rich alcohol-soluble neutral conjugated polymersas highly efficient electron-injecting materials for polymer light-emitting diodes. Adv. Func.Mater.,2009,19(15):2457-2466
[73] H. B. Wu, F. Huang, Y. Q. Mo, et al. Efficient electron injection from a bilayer cathodeconsisting of aluminum and alcohol-/water-soluble conjugated polymers. Adv. Mater.,2004,16(20):1826-1830
[74] W. L. Ma, P. K. Iyer, X. Gong, et al. Water/methanol-soluble conjugated copolymer as anelectron-transport layer in polymer light-emitting diodes. Adv. Mater.,2005,17(3):274-277
[75] R. Q. Yang, H. B. Wu, Y. Cao, et al. Control of cationic conjugated polymer performance inlight emitting diodes by choice of counterion. J. Am. Chem. Soc.,2006,128(45):14422-14423
[76] J. Kido, M. Kimura, and K. Nagai. Multilayer white light-emitting organic electroluminescentdevice. Science.,1995,267(5202):1332-1334
[77] B. W. D’Andrade, S. R. Forrest. White organic light-emitting devices for solid-state lighting.Adv. Mater.,2004,16(18):1585-1595
[78] K. T. Kamtekar, A. P. Monkman, and M. R. Bryce. Recent advances in white organiclight-emitting materials and devices (WOLEDs). Adv. Mater.,2010,22(5):572-582
[79] M. C. Gather, A. K hnen, and K. Meerholz. White organic light-emitting diodes. Adv. Mater.,2011,23(2):233-248
[80] L. Xiao, Z. Chen, B. Qu, et al. Recent progresses on materials for electrophosphorescentorganic light-emitting devices. Adv. Mater.,2011,23(8):926-952
[81] Q. Xu, H. M. Duong, F. Wudl, et al. Efficient single-layer “twistacene”-doped polymer whitelight-emitting diodes. Appl. Phys. Lett.,2004,85(16):3357-3359
[82] Y. R. Sun and S. R. Forrest. High-efficiency white organic light emitting devices with threeseparate phosphorescent emission layers. Appl. Phys. Lett.,2007,91(26):263503-1-3
[83] X. Gong, W. Ma, J. C. Ostrowski, et al. White electrophosphorescence from semiconductingpolymer blends. Adv. Mater.,2004,16(7):615-619
[84] X. Gong, S. Wang, D. Moses, et al. Multilayer polymer light-emitting diodes: white-lightemission with high efficiency. Adv. Mater.,2005,17(17):2053-2058
[85] J. H. Jou, M. C. Sun, H. H. Chou, et al. Efficient pure-white organic light-emitting diodes with asolution-processed, binary-host employing single emission layer. Appl. Phys. Lett.,2006,88(14):141101-1-3
[86] P. I. Shih, Y. H. Tseng, F. I. Wu, et al. Stable and efficient white electroluminescent devicesbased on a single emitting layer of polymer blends. Adv. Funct. Mater.,2006,16(12):1582-1589
[87] Y. H. Xu, J. B. Peng, J. X. Jiang, et al. Efficient white-light-emitting diodes based on polymercodoped with two phosphorescent dyes. Appl. Phys. Lett.,2005,87(19):193502-1-3
[88] H. Wu, J. Zou, F. Liu, et al. Efficient single active layer electrophosphorescent white polymerlight-emitting diodes. Adv. Mater.,2008,20(4):696-702
[89] F. Huang, P. Shih, C. F. Shu, et al. Highly efficient polymer white-light-emitting diodes basedon lithium salts doped electron transporting layer. Adv. Mater.,2009,21(3):361-365
[90] B. W. D’Andrade, M. E. Thompson, and S. R. Forrest. Controlling exciton diffusion inMultilayer white phosphorescent organic light emitting devices. Adv. Mater.,2002,14(2):147-151
[91] Y. Sun, N. C. Giebink, and H. Kanno. Management of singlet and triplet excitons for efficientwhite organic light-emitting devices. Nature.,2006,440(7086):908-912
[92] G. Schwartz, S. Reineke, T. C. Rosenow, et al. Triplet harvesting in hybrid white organiclight-emitting diodes. Adv. Funct. Mater.,2009,19(9):1319-1333
[93] B. W. D’Andrade, R. J. Holmes, and S. R. Forrest. Efficient organic electrophosphorescentwhite-light-emitting device with a triple doped emissive layer. Adv. Mater.,2004,16(7):624-628
[94] M. Sun, C. Zhong, F. Li, et al. A fluorine-oxadiazole copolymer for white light-emittingelectrochemical cells. Macromolecules.,2010,43(4):1714-1718
[95] E. L. Williams, K. Haavisto, J. Li, et al. Excimer-based white phosphorescent organic light-emitting diodes with nearly100%internal quantum efficiency. Adv. Mater.,2007,19(2):197-202
[96] J. X. Jiang, Y. H. Xu, W. Yang, et al. High-efficiency white-light-emitting devices from asingle polymer by mixing singlet and triplet emission. Adv. Mater.,2006,18(13):1769-1773
[97] J. Liu, Q. G. Zhou, Y. X. Cheng, et al. White electroluminescence from a single-polymersystem with simultaneous two-color emission: polyfluorene as the blue host and a2,1,3-benzothia-diazole derivative as the orange dopant. Adv. Funct. Mater.,2006,16(7):957-965
[98] H. J. Peng, X. L. Zhu, J. X. Sun, et al. Efficiency improvement of phosphorescent organiclight-emitting diodes using semitransparent Ag as anode. Appl. Phys. Lett.,2006,88(3):033509-1-3
[99] R. J. Holmes, S. R. Forrest, Y. J. Tung, et al. Blue organic electrophosphorescence usingexothermic host–guest energy transfer. Appl. Phys. Lett.,2003,82(15):2422-2424
[100] L. Zeng, T. Y. Lee, P. Merkel, et al. A new class of non-conjugated bipolar hybrid hosts forphosphorescent organic light-emitting diodes. J. Chem. Mater.,2009,19(46):8772-8781
[101] C. Yang, C. Tai, and I. Sun. Synthesis of a high-efficiency red phosphorescent emitter fororganic light-emitting diodes. J. Chem. Mater.,2004,14(6):947-950
[102] J. Wang, Y. D. Jiang, J. S. Yu, et al. Low operating voltage bright organic light-emitting diodeusing iridium complex doped in4,4′-bis[N-1-napthyl-N-phenyl-amino] biphenyl. Appl. Phys.Lett.,2007,91(13):131105-1-3
[103] J. Wang, J. Yu, L. Li, et al. Low roll-off power efficiency organic light-emitting diodesconsisted of nondoped ultrathin phosphorescent layer. Appl. Phys. Lett.,2008,92(13):133308-1-3
[104] M. A. Baldo, C. Adachi, and S. R. Forrest. Transient analysis of organic electrophosphoresc-ence. II. Transient analysis of triplet-triplet annihilation. Phys. Rev. B.,2000,62(16):10967-10977
[105] S. Reineke, K. Walzer, and K. Leo. Triplet-exciton quenching in organic phosphorescentlight-emitting diodes with Ir-based emitters. Phys. Rev. B.,2007,75(12):125328-1-13
[106] J. Kalinowski, W. Stampor, and J. Mezyk. Quenching effects in organic electrophosphores-cence. Phys. Rev. B.,2002,66(23):235321-1-15
[107] L. Li, J. Liu, Z. Yu, et al. Highly efficient blue phosphorescent polymer light-emitting diodesby using interfacial modification. Appl. Phys. Lett.,2011,98(20):201110-1-3
[108] X. Gong, S. H. Lim, J. C. Ostrowski, et al. Phosphorescence from iridium complexes dopedinto polymer blends. J. Appl. Phys.,2004,95(3):948-953
[109] C. Adachi, M. A. Baldo, and S. R. Forrest. Electroluminescence mechanisms in organic lightemitting devices employing a europium chelate doped in a wide energy gap bipolarconducting host. J. Appl. Phys.,2000,87(11):8049-8055
[110] P. A. Lane, L. C. Palilis, D. F. O’Brien, et al. Origin of electrophosphorescence from a dopedpolymer light emitting diode. Phys. Rev. B.,2001,63(23):235206-1-8
[111] B. Hu, F. E. Karasz, Blue, green, red, and white electroluminescence from multichromophorepolymer blends. J. Appl. Phys.,2003,93(4):1995-2001
[112] M. Gather, R. Alle, H. Becker, et al. On the Origin of the Color Shift in White-EmittingOLEDs. Adv. Mater.,2007,19(24):4460-4465
[113] G. Gustafsson, Y. Cao, G. M. Treacy, et al. A. J. Heeger, Flexible light-emitting diodes madefrom soluble conducting polymers. Nature,1992,357:477-479
[114] G. Gu, P. E. Burrows, S. Venkatesh, et al. Vacuum-deposited, nonpolymeric flexible organiclight-emitting devices. Opt. Lett.,1997,22(3):172-174.
[115] T. R. Hebner, C. C. Wu, D. Marcy, et al. Ink-jet printing of doped polymers for organic lightemitting devices. Appl. Phys. Lett.,1998,72(5):519-511.
[116] H. Yang, Z. Wang, S. Madakuni, et al. Highly efficient excimer-based white phosphorescentdevices with improved power efficiency and color rendering index. Appl. Phys. Lett.,2008,93(19):193305.
[117] Z. Yu, L. Hu, Z. Liu, et al. Fully bendable polymer light emitting devices with carbonnanotubes as cathode and anode. Appl. Phys. Lett.,2009,95(20):203304.
[118] M. A. Ibrahim, H. K. Roth, M. Schroedner, et al. The influence of the optoelectronicproperties of poly(3-alkylthiophenes) on the device parameters in flexible polymer solar cells.Org. Electron.,2005,6(2):65-77.
[119] R. Paetzold, K. Heuser, D. Henseler, et al. Performance of flexible polymeric light-emittingdiodes under bending conditions. Appl. Phys. Lett.,2003,82(19):3342-3344.
[120] W. A. Gazotti, G. C. Miceli, A. Geri, et al. An all-plastic and flexible electrochromic devicebased on elastomeric blends. Adv. Mater.,1998,10(18):1522-1525.
[121] Y. Yang, Q. Huang, A. W. Metz, et al. High-performance organic light-emitting diodes usingITO anodes grown on plastic by room-temperature ion-assisted deposition. Adv. Mater.,2004,16(4):321-324.
[122] J. Y. Lee, S. T. Connor, Y. Cui, et al. Solution-processed metal nanowire mesh transparentelectrodes. Nano Lett.,2008,8(2):689-692.
[123] S. De, T. M. Higgins, P. E. Lyons, et al. Silver nanowire networks as flexible, transparent,conducting films: extremely high DC to optical conductivity ratios. ACS Nano,2009,3(7):1767-1774.
[124] W. Gaynor, J. Y. Lee, Fully Solution-processed inverted polymer solar cells with laminatednanowire electrodes, P. Peuman. ACS Nano,2010,4(1):30-34.
[125] L. Hu, D. S. Hecht, G. Gruner, Percolation in transparent and conducting carbon nanotubenetworks. Nano Lett.,2004,4(12):2513-2517
[126] J. Li, L. Hu, L. Wang, et al. Organic light-emitting diodes having carbon nanotube anodes.Nano Lett.,2006,6(11):2472-2477.
[127] W. Yuan, L. B. Hu, Z. B. Yu, et al. Fault-tolerant dielectric elastomer actuators usingsingle-walled carbon nanotube electrodes. Adv. Mater.,2008,20(3):621-625.
[128] D. Azulai, T. Belenkova, H. Gilon, et al. Transparent metal nanowire thin films prepared inmesostructured templates, G. Markovich. Nano Lett.,2009,9(12):4246-4249.
[129] Z. Hou, C. K. Tsung, W. Huang, et al. Sub-two nanometer single crystal Au nanowires. NanoLett.,2008,8(7):2041-2044.
[130] X. Lu, M. S. Yavuz, H. Y. Tuan, et al. Ultrathin gold nanowires can be obtained by reducingpolymeric strands of oleylamine AuCl complexes formed via aurophilic interaction. J. Am.Chem. Soc.,2008,130(28):8900-8901.
[131] C. Wang, Y. Hu, C. M. Lieber, et al. Ultrathin Au nanowires and their transport properties. J.Am. Chem. Soc.,2008,130(28):8902-8903.
[132] Z. Yu, X. Niu, Z. Liu, et al. Intrinsically stretchable polymer light-emitting devices usingcarbon nanotube-polymer composite electrodes. Adv. Mater.,2011,23(34):3989-3994.
[133] Y. G. Sun, B. Gates, B. Mayers, et al. Crystalline silver nanowires by soft solution processing.Nano Lett.,2002,2(2):165-168.
[134] K. K. Kim, S. D. Lee, H. Kim, et al. Enhanced light extraction efficiency of GaN-basedlight-emitting diodes with ZnO nanorod arrays grown using aqueous solution. Appl. Phys.Lett.,2009,94(7):071118.
[135] X. Yang, D. Neher, D. Hertel, et al. Highly efficient single-layer polymerelectrophosphorescent devices. Adv. Mater.,2004,16(2):161-166.
[136] F. I. Wu, H. J. Su, C. F. Shu, et al. Tuning the emission and morphology of cyclometalatediridium complexes and their applications to organic light-emitting diodes. J. Mater. Chem.,2005,15(10):1035-1042.
[137] M. Suzuki, S. Tokito, F. Sato, T. Igarashi, K. Kondo, et al. Highly efficient polymerlight-emitting devices using ambipolar phosphorescent polymers. Appl. Phys. Lett.,2005,86(10):103507.
[138] Z. Wu, L. Wang, G. Lei, et al. Investigation of the spectra of phosphorescent organiclight-emitting devices in relation to emission zone. J. Appl. Phys.,2005,97(10):103105.
[139] J. Zou, H. Wu, C. Lam, et al. Simultaneous optimization of charge-carrier balance andluminous efficacy in highly efficient white polymer light-emitting devices. Adv. Mater.,2011,23(26):2976-2980
[140] C. Adachi, M. A. Baldo, M. E. Thompson, et al. Nearly100%internal phosphorescenceefficiency in an organic light-emitting device. J. Appl. Phys.,2001,90(10):5048-5051
[141] A. Chutinan, K. Ishihara, T. Asano, et al. Theoretical analysis on light-extraction efficiency oforganic light-emitting diodes using FDTD and mode-expansion methods. Org. Electron.,2005,6(1):3-9
[142] V. Bulovic, V. B. Khalfin, G. Yu, et al. Weak microcavity effects in organic light-emittingdevices. Phys. Rev. B,1998,58(7):3730-3740
[143] K. Saxena, V. K. Jain, D. Mehta. A review on the light extraction techniques in organicelectroluminescent devices. Opt. Mater.,2009,32(1):221-233
[144] J. Kim, P. K. H. Ho, N. C. Greenham, et al. Electroluminescence emission pattern of organiclight-emitting diodes: Implications for device efficiency calculations. J. Appl. Phys.,2000,88(2):1073-1081
[145] M. H. Lu, J. C. Sturn, External coupling efficiency in planar organic light-emitting devices.Appl. Phys. Lett.,2001,78(13):1927-1929
[146] T. Nakamura, N. Tsutsumi, N. Juni, et al. Thin-film waveguiding mode light extraction inorganic electroluminescent device using high refractive index substrate. J. Appl. Phys.,2005,97(5),054505
[147] Y. H. Cheng, J. L. Wu, C. H. Cheng. Enhanced light outcoupling in a thin film by texturingmeshed surfaces. Appl. Phys. Lett.,2007,90(9):091102
[148] J. M. Ziebarth, A. K. Saafir, S. Fan, et al. Extracting light from polymer light-emitting diodesusing stamped bragg gratings. Adv. Funct. Mater.,2004,14(5):451-456
[149] J. J. Shiang, T. J. Faircloth, A. R. Duggal, Experimental demonstration of increased organiclight emitting device output via volumetric light scattering. J. Appl. Phys.,2004,95(5):2889-2895
[150] F. Li, X. Li, J. Zhang, et al. Enhanced light extraction from organic light-emitting devices byusing microcontact printed silica colloidal crystals. Org. Electron.,2007,8(5):635-639
[151] S. Moller, S. R. Forrest, Improved light out-coupling in organic light emitting diodesemploying ordered microlens arrays. J. Appl. Phys.,2002,91(5):3324-3327
[152] M. Wei, I. Su, Method to evaluate the enhancement of luminance efficiency in planar OLEDlight emitting devices for microlens array. Opt. Exp.,2004,12(23):5777-5782
[153] T. Shiga, H. Fujikawa, Y. Taga, Design of multiwavelength resonant cavities for white organiclight-emitting diodes. J. Appl. Phys.,2003,93(1):19-22
[154] T. Cho, C. Lin, C. Wu, Microcavity two-unit tandem organic light-emitting devices having ahigh efficiency. Appl. Phys. Lett.,2006,88(11):111106
[155] Y. R. Do, Y. Kim, Y. Song, et al. Enhanced light extraction efficiency from organic lightemitting diodes by insertion of a two-dimensional photonic crystal structure. J. Appl. Phys.,2004,96(12):7629-7636
[156] C. Liu, V. Kamaev, Z. V. Vardeny, Efficiency enhancement of an organic light-emitting diodewith a cathode forming two-dimensional periodic hole array. Appl. Phys. Lett.,2005,86(14):143501
[157] S. Noda, M. Fujita, T. Asano, Spontaneous-emission control by photonic crystals andnanocavities. Nat. Photonics,20071(8):449-458
[158] E. Ozbay, Plasmonics: merging photonics and electronics at nanoscale dimensions. Science,2006,311(5758):189-193
[159] Y. Bao, B. Zhang, Z. Wu, et al. Surface-plasmon-enhanced transmission through metallic filmperforated with fractal-featured aperture array. Appl. Phys. Lett.,2007,90(25):251914
[160] H. J. Peng, Y. L. Ho, X. J. Yu, et al. Enhanced coupling of light from organic light emittingdiodes using nanoporous films. J. Appl. Phys.,2004,96(3):1649-1654
[161] M. Agarwal, Y. Sun, S. R. Forrest, et al. Enhanced outcoupling from organic light-emittingdiodes using aperiodic dielectric mirrors. Appl. Phys. Lett.,2007,90(24):241112
[162] T. Tsutsui, M. Yahiro, H. Yokogawa, et al. Doubling coupling-out efficiency in organiclight-emitting devices using a thin silica aerogel layer. Adv. Mater.,2001,13(15):1149-1152
[163] W. Koo, S. Jeong, F. Araoka, et al. Light extraction from organic light-emitting diodesenhanced by spontaneously formed buckles. Nat. Photonics,2010,4(4):222-226