新型离子型铱配合物的设计、合成及其在发光电化学池中的应用
|
摘要
有机电致发光器件(OLEDs)在当今社会人类知识的获得和生活质量的改善方面扮演着越来越重要角色,有着巨大的应用潜力和广阔的商业前景,而发光电化学池(LECs)是有机电致发光器件的一个重要分支。近年来离子型过渡金属配合物(iTMCs)由于能够应用于发光电化学池而备受瞩目。离子型过渡金属配合物具有离子传导性,以经典的离子型金属配合物[Ru(bpy)_3]~(2+)(PF_6~-)_2为例,PF_6~-的平衡离子在外加电压下能够重组,这种行为可以在每个电极附近产生离子空间电荷(其余PF_6~-在阳极,无补偿的[Ru(bpy)3]2+则在阴极),以协助电子电荷注入,甚至可以使电子更好地从空气稳定的金属电极注入,此种器件就类似于所谓的发光电化学电池(LECs);另外,离子型过渡金属配合物发光效率极高,其发光量子率可达100%,从这些材料中产生的辐射几乎全部来自三重态辐射。在器件制备方面,离子型过渡金属配合物一般可直接旋涂成膜。这些性能都表明单层膜离子型过渡金属配合物完全可以被制成高效能有机电致发光器件。
离子型铱配合物除了具备中性铱配合物所具备的发光效率高、发射波长可调等优点外,还具有一些中性铱配合物所不具备的特性,使之有可能成为一种更好的电致发光材料。首先,与中性铱配合物相比,离子型铱配合物的合成条件更温和;其次,基于离子型铱配合物的发光材料可以采用惰性金属(如金)作电极得到高效电致发光器件;再次,这类配合物具有稳定的氧化一还原可逆性,有利于提高器件稳定性;另外,由于此类配合物携带电荷和抗衡离子,所以有利于载流子注入和迁移,降低器件能耗。但是,由于此类配合物携带电荷,导致这类配合物与疏水的共轭主体材料之间的相容性差,从而影响其在电致发光器件中的应用。本论文所研究的主要内容是解决配合物与疏水的共轭主体材料之间的相容性问题,对配体分子结构进行改性,设计、合成出新型的、具有较高发光效率的离子型配合物,从而获得高亮度,低电压,高效率的高效电致发光器件。
本论文研究内容如下:
1.设计、合成了两种含有1,3,4-噁二唑和吡啶基团的新型的N^N配体mptop和ptop,其中mptop代表2-(2-吡啶基)-5-(4-甲基苯基)-1,3,4-噁二唑2-(5-phenyl-[1,3,4]oxadiazol-2-yl)-pyridine,ptop代表2-(2-吡啶基)-5-苯基-1,3,4噁二唑2-(5-p-Tolyl-[1,3,4]oxadiazol-2-yl)-pyridine及其两种配体的离子型铱的配合物[Ir(mptop)(ppy)_2]~+(PF_6~-)和[Ir(ptop)(ppy)_2]~+(PF_6~-)。大量研究表明,1,3,4-噁二唑具有优良的电子传输性、良好的发光性能、热稳定性及化学稳定性,是一类应用和研究最广的电子传输材料之一。我们合成了以1,3,4-噁二唑作为结构单元的新型N^N配体。在此类配体的基础上合成了一系列离子型铱配合物,通过红外光谱、核磁及单晶结构解析等手段对配合物结构进行了表征。
2.我们对这些配合物的光物理、电化学性质进行了详细的研究。通过对配合物的紫外-可见吸收、光致发光性质及量化计算的研究,详细讨论了这些配合物的激发态性质,阐明了配体的化学结构与配合物的光物理和电化学性质之间的关系。
3.分别制备了两种配合物的发光电化学池器件,从器件的启亮电压、响应时间、最大亮度、发光效率及寿命等方面研究了配合物分子结构的改变对器件性能的影响。
Nowdays, organic light emitting diodes(OLEDs) are planing increasingly important role in the acquisition of knowledge and improvement quality of life for people,They have Has great potential and broad prospects for business,However, light-emitting electrochemical cells(LECs) are an important branchs of OLEDs.Recently dramatic advances have been achieved in the field of LECs, which are being developed for display and lighting applications. Ionic transition metal complexes (iTMCs) offer an alternative to such processing associated with conventional OLEDs.Their excellent stability in multiple redox states implies that electronic charges can be readily injected and transported. Furthermore, iTMCs such as [Ru(bpy)_3]~(2+)(PF_6~-)2 are ionically conducting as the PF_6~- counterions can redistribute under an applied bias. This action creates an ionic space charge near each electrode (excess PF_6~- at the anode and uncompensated [Ru(bpy)_3]~(2+) at the cathode), which serves to assist electronic charge injection, even to the point of efficiently injecting electrons from air-stable metals. In this manner, these devices are similar to the socalled light-emitting electrochemical cells (LECs), which are fabricated by dispersing salts into organic semiconductors. Additionally, the luminescence efficiency of iTMCs can be extremely high, with photoluminescence quantum yields approaching 100%, as emission from these materials arises almost exclusively from triplet states. As for processing, iTMCs can generally be spin cast directly from solution. These properties indicate that efficient electroluminescent devices can be fabricated from single-layer iTMC devices.
Charged iridium(Ir) complexes have many other features except for high quantum efficiencies and easily tunable emission wavelength that may make them one of the finest candidates for lightings, displays and light-emitting electrochemical cells (LECs). First, the synthesis condition of charged Ir complexes is much milder than that of neutral ones. Second, inert metal electrodes resistant to oxidation in air, such as Au and Pt, can be used in efficient devices based on charged Ir complexes. Third, further improving the stability of devices can be expected due to their excellent redox stabilities. In addition, charged Ir complexes are endorsed with the properties of charge transfer, consequently lowering power consumptions of devices. However, for the blend system of charged Ir complexes into hydrophobic host materials, the problem of phase separation is more serious them that of neutral Ir complexes due to the poor compatibility. And this problem is an obstacle to their applications in organic electronics. In order to solve this problem, modify the structure of ligands should to be done, and design, synthesize novel ionic iridium(Ir) complexes of high luminous efficiency to arrive LEC of high luminescence, high efficiency, This dissertation is comprised of the follow two parts:
1、Two novel ligands (mptop and ptop) contain 1,3,4--oxadiazole and pyridine were designed and synthesized, and two ionic iridium(Ir) complexes [Ir(mptop)(ppy)_2]~+(PF_6~-)and [Ir(ptop)(ppy)_2]~+(PF_6~-) were prepared, where mptop is 2-(5-p-Tolyl-[1,3,4]oxadiazol-2-yl)- pyridine, ptop is 2-(5-Phenyl-[1,3,4]oxadiazol-2-yl)-pyridine, Compounds containing 1,3,4-oxadiazole(OXA) which possess excellent electron affinity, good light-emitting, thermal stability, and chemical stability characteristic, are commonly used as electron transporting and hole blocking materials in OLEDs. All of the complexes were characterized by IR, 1HNMR and X-Ray diffraction. Initiative study showed that the complexes were expected to be a good candidate for lighting and display application.
2、Photophysical and electrochemical properties of these complexes were investigated, By study the UV-visible absorption spectrum, fluorescence emission spectrum and theoretical calculations of the complexes, we received that complexes with different ligands showed different optoelectronic properties and all complexes exhibited intense and long-live emission, clarified that the relationship between chemical structure and complexes,properties in photophysics and electrochemistry.
3.We fabricated organic red light-emitting electrochemical cells (LECs) based on the two complexes [Ir(mptop)(ppy)_2]~+(PF_6~-) and [Ir(ptop)(ppy)_2]~+(PF_6~-) respectively. from devices, start-up voltage, response time, maximum brightness, luminous efficiency and device life, we studied the molecular structure of the complex changes in the impact on device performance.
离子型铱配合物除了具备中性铱配合物所具备的发光效率高、发射波长可调等优点外,还具有一些中性铱配合物所不具备的特性,使之有可能成为一种更好的电致发光材料。首先,与中性铱配合物相比,离子型铱配合物的合成条件更温和;其次,基于离子型铱配合物的发光材料可以采用惰性金属(如金)作电极得到高效电致发光器件;再次,这类配合物具有稳定的氧化一还原可逆性,有利于提高器件稳定性;另外,由于此类配合物携带电荷和抗衡离子,所以有利于载流子注入和迁移,降低器件能耗。但是,由于此类配合物携带电荷,导致这类配合物与疏水的共轭主体材料之间的相容性差,从而影响其在电致发光器件中的应用。本论文所研究的主要内容是解决配合物与疏水的共轭主体材料之间的相容性问题,对配体分子结构进行改性,设计、合成出新型的、具有较高发光效率的离子型配合物,从而获得高亮度,低电压,高效率的高效电致发光器件。
本论文研究内容如下:
1.设计、合成了两种含有1,3,4-噁二唑和吡啶基团的新型的N^N配体mptop和ptop,其中mptop代表2-(2-吡啶基)-5-(4-甲基苯基)-1,3,4-噁二唑2-(5-phenyl-[1,3,4]oxadiazol-2-yl)-pyridine,ptop代表2-(2-吡啶基)-5-苯基-1,3,4噁二唑2-(5-p-Tolyl-[1,3,4]oxadiazol-2-yl)-pyridine及其两种配体的离子型铱的配合物[Ir(mptop)(ppy)_2]~+(PF_6~-)和[Ir(ptop)(ppy)_2]~+(PF_6~-)。大量研究表明,1,3,4-噁二唑具有优良的电子传输性、良好的发光性能、热稳定性及化学稳定性,是一类应用和研究最广的电子传输材料之一。我们合成了以1,3,4-噁二唑作为结构单元的新型N^N配体。在此类配体的基础上合成了一系列离子型铱配合物,通过红外光谱、核磁及单晶结构解析等手段对配合物结构进行了表征。
2.我们对这些配合物的光物理、电化学性质进行了详细的研究。通过对配合物的紫外-可见吸收、光致发光性质及量化计算的研究,详细讨论了这些配合物的激发态性质,阐明了配体的化学结构与配合物的光物理和电化学性质之间的关系。
3.分别制备了两种配合物的发光电化学池器件,从器件的启亮电压、响应时间、最大亮度、发光效率及寿命等方面研究了配合物分子结构的改变对器件性能的影响。
Nowdays, organic light emitting diodes(OLEDs) are planing increasingly important role in the acquisition of knowledge and improvement quality of life for people,They have Has great potential and broad prospects for business,However, light-emitting electrochemical cells(LECs) are an important branchs of OLEDs.Recently dramatic advances have been achieved in the field of LECs, which are being developed for display and lighting applications. Ionic transition metal complexes (iTMCs) offer an alternative to such processing associated with conventional OLEDs.Their excellent stability in multiple redox states implies that electronic charges can be readily injected and transported. Furthermore, iTMCs such as [Ru(bpy)_3]~(2+)(PF_6~-)2 are ionically conducting as the PF_6~- counterions can redistribute under an applied bias. This action creates an ionic space charge near each electrode (excess PF_6~- at the anode and uncompensated [Ru(bpy)_3]~(2+) at the cathode), which serves to assist electronic charge injection, even to the point of efficiently injecting electrons from air-stable metals. In this manner, these devices are similar to the socalled light-emitting electrochemical cells (LECs), which are fabricated by dispersing salts into organic semiconductors. Additionally, the luminescence efficiency of iTMCs can be extremely high, with photoluminescence quantum yields approaching 100%, as emission from these materials arises almost exclusively from triplet states. As for processing, iTMCs can generally be spin cast directly from solution. These properties indicate that efficient electroluminescent devices can be fabricated from single-layer iTMC devices.
Charged iridium(Ir) complexes have many other features except for high quantum efficiencies and easily tunable emission wavelength that may make them one of the finest candidates for lightings, displays and light-emitting electrochemical cells (LECs). First, the synthesis condition of charged Ir complexes is much milder than that of neutral ones. Second, inert metal electrodes resistant to oxidation in air, such as Au and Pt, can be used in efficient devices based on charged Ir complexes. Third, further improving the stability of devices can be expected due to their excellent redox stabilities. In addition, charged Ir complexes are endorsed with the properties of charge transfer, consequently lowering power consumptions of devices. However, for the blend system of charged Ir complexes into hydrophobic host materials, the problem of phase separation is more serious them that of neutral Ir complexes due to the poor compatibility. And this problem is an obstacle to their applications in organic electronics. In order to solve this problem, modify the structure of ligands should to be done, and design, synthesize novel ionic iridium(Ir) complexes of high luminous efficiency to arrive LEC of high luminescence, high efficiency, This dissertation is comprised of the follow two parts:
1、Two novel ligands (mptop and ptop) contain 1,3,4--oxadiazole and pyridine were designed and synthesized, and two ionic iridium(Ir) complexes [Ir(mptop)(ppy)_2]~+(PF_6~-)and [Ir(ptop)(ppy)_2]~+(PF_6~-) were prepared, where mptop is 2-(5-p-Tolyl-[1,3,4]oxadiazol-2-yl)- pyridine, ptop is 2-(5-Phenyl-[1,3,4]oxadiazol-2-yl)-pyridine, Compounds containing 1,3,4-oxadiazole(OXA) which possess excellent electron affinity, good light-emitting, thermal stability, and chemical stability characteristic, are commonly used as electron transporting and hole blocking materials in OLEDs. All of the complexes were characterized by IR, 1HNMR and X-Ray diffraction. Initiative study showed that the complexes were expected to be a good candidate for lighting and display application.
2、Photophysical and electrochemical properties of these complexes were investigated, By study the UV-visible absorption spectrum, fluorescence emission spectrum and theoretical calculations of the complexes, we received that complexes with different ligands showed different optoelectronic properties and all complexes exhibited intense and long-live emission, clarified that the relationship between chemical structure and complexes,properties in photophysics and electrochemistry.
3.We fabricated organic red light-emitting electrochemical cells (LECs) based on the two complexes [Ir(mptop)(ppy)_2]~+(PF_6~-) and [Ir(ptop)(ppy)_2]~+(PF_6~-) respectively. from devices, start-up voltage, response time, maximum brightness, luminous efficiency and device life, we studied the molecular structure of the complex changes in the impact on device performance.
引文
[1] deMello J C.Interfacial feedback dynamics in polymer light-emitting electrochemical cells[J].Physical Review B,2002,66,235210.
[2] Gorodetsky A A,Parker S,Slinker J D,et al.Contact issues in electroluminescent devices from ruthenium complexes[J].Applied Physics Letters,2004,84,807–809.
[3] Holder E,Langeveld B M,Schubert U S,et al.New trends in the use of transition metal-ligand complexes for applications in electroluminescent devices[J].Advanced Material,2005,17,1109–1121.
[4] Slinker J D,Parker J B,Abru?a H D,et al.Electroluminescent devices from ionic transition metal complexes[J].Journal of Material Chemistry,2007,17,2976–2988.
[5] Pope M, Kallmann H P,Magnante P,et al.Electroluminescence in organic crystals[J].J Chem Phys, 1963,38(8),2042-2043.
[6] Vincett P S,Barlow W A,Hann R A,et al.Eectrical conduction and low voltage blue electroluminescence in vacuum-deposited organic film[J].Thin Solid Films,1982,94,171.
[7] Gau E J,Macdiarmjol S C,Physical Review Letters,1977,39,1098.
[8] Tang C W,Vanslyke S A,et al.Organic eletrouminescenec diodes[J].Applied Physics Letters,1987, 51(12),913.
[9] Pei Q B,Yu G,Yang Y,et al.Polymer light-emitting electrochemical-cells[J].Science,1995, 269,1086–1088.
[10] Lee J,Chu H Y,Do L M,et al.High efficiency organic light-emitting devices with Al/NaF cathode[J].Appl Phys Lett,2003,82(2),173-175.
[11] Pei Q B,Yang Y,Zhang C,et al.Polymer light-emitting electrochemical cells:In situ formation of a light-emitting p?n junction[J].J Am Chem Soc ,1996,118(16),3922-3929.
[12] Ouisse T,Armand M,Kervella Y,et al.Fully transparent organic light-emitting electrochemical cells[J].Appl Phys Lett.2002,81(17),3131-3133.
[13] Lyons C H,Abbas E D,Lee J K,et al.Solid-state light-emitting devices based on the trischelated ruthenium(II) complex[J].J Am Chem Soc,1998,120(46),12100-12107.
[14] Handy E S,Pal A J,Rubner M F.Solid-state light-emitting devices based on the tris-chelated ruthenium(II) complex as a high-brightness emitter[J].J Am Chem Soc,1999,121(14),3525-3528.
[15] Wu A,Yoo D,Lee J K,et al.Solid-state light-emitting devices based on the tris-chelated ruthenium(II) complex:high efficiency devices via a layer-by-Layer molecular-level blending approach[J].J Am Chem Soc,1999,121(20),4883-4891.
[16] Gao F G , Bard A J , Solid-state organic light-Emitting diodes based on Tris(2,2‘-bipyridine)ruthenium(II) complexes[J].J Am Chem Soc.2000,122(30),7426-7427.
[17] Rudmann H,Rubner M F.Single layer light-emitting devices with high efficiency and long lifetime based on tris(2,2′-bipyridyl) ruthenium(II) hexafluorophosphate[J].J Appl Phys,2001,90(9),4338-4345.
[18] Bernhard S,Barron J A,Houston P L,et al.Electroluminescence in ruthenium(II) complexes[J].J Am Chem Soc,2002,124(45),13624-13628.
[19] Buda M,Kalyuzhny G,Bard A J,Thin-film solid-state electroluminescent devices based onTris(2,2′-bipyridine) ruthenium(II) complexes[J].J.Am Chem Soc,2002,124(21),6090-6098.
[20] Gao F G,Bard A. J.High-brightness and low-voltage light-emitting devices based on trischelated ruthenium(II) and tris(2,2‘-bipyridine) osmium(II) emitter layers and low melting point alloy cathode contacts[J].Chem Mat,2002,14(8),3465-3470.
[21] Lepretre J C,Deronzier A,Stephan O,Light-emitting electrochemical cells based on ruthenium(II) using crown ether as solid electrolyte [J].Syn Met,2002,131(1-3),175-183.
[22] Rudmann H,Shimada S,Rubner M F,et al.Solid-state light-emitting devices based on the tris-chelated ruthenium(II) complex:.high-efficiency light-emitting devices based on derivatives of the tris(2,2‘-bipyridyl) ruthenium(II) complex[J].J Am Chem Soc,2002,124(17),4918-4921.
[23] Rudmann H,Shimada S,Rubner M F,et al.Prevention of the cathode induced electrochemical degradation of [Ru(bpy)3](PF6)2 light emitting devices[J].J Appl Phys,2002,92(3),1576-1581.
[24] Kalyuzhny G,Buda M,McNeill J,et al.Stability of thin-film solid-state electroluminescent devices based on tris(2,2‘-bipyridine)ruthenium(II) complexes[J].J.Am.Chem.Soc,2003,125(20), 6272-6283.
[25] Rudmann H,Shimada S,Rubner M F.Operational mechanism of light-emitting devices based on Ru(II) complexes:Evidence for electrochemical junction formation[J].J Appl Phys.2003,94(1),115-122.
[26] Slinker J D,Houston P L,Abruna H D,et al.Solid-state electroluminescent device based on transition metal complexes[J].Chem Commun,2003,(19),2392-2399.
[27] Yang J H , Gordon K C , Zidon Y , et al . Light-emitting devices based on ruthenium(II)(4,7-diphenyl-1,10-phenanthroline)3:Device response rate and efficiency by use of tris-(8-hydroxyquinoline) aluminum[J].J Appl Phys,2003,94(10),6391-6395.
[28] Chuai Y T,Lee D N,Zhen C G,et al.Novel polypyridyl ruthenium(II) complexes for electroluminescence [J].Syn Met,2004,145(2-3),259-264.
[29] Gorodetsky A A,Parker S,Slinker J D,et al.Contact issues in electroluminescent devices from ruthenium complexes[J].Appl Phys Lett,2004,84(5),807-809.
[30] Liu C Y , Bard A J . Highly efficient and bright electroluminescent Ru(bpy)3(ClO4)2/Alq3 device[J].Appl Phys Lett,2005,87(6),61110.
[31] Pile D L , Bard A J . Effect of water vapor on the operation and stability of tris(2,2‘-bipyridine)ruthenium(II)-Based light-emitting electrochemical cells [J].Chem Mat,2005,17(16),4212-4217.
[32] Zhao W,Liu C Y,Wang Q,et al.Effect of residual solvent on ru(bpy)3(ClO4)2-based light-emitting electrochemical cells[J].Chem Mat.2005,17(25),6403-6406.
[33] Bolink H J,Cappelli L,Coronado E,et al.Efficient and stable solid-state light-emitting electrochemical cell using tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) hexafluorophosphate[J].J Am Chem Soc,2006,128(1),46-47.
[34] Jia W L,Hu Y F,Gao J,et al.Linear and star-shaped polynuclear Ru(II) complexes of 2-(2′-pyridyl)benzimidazolyl derivatives:syntheses,photophysical properties and red light-emitting devices[J].Dalton Trans,2006,14,1721-1728.
[35] Parker S T,Slinker J D,Lowry M S,et al.Improved turn-on times of Iridium electroluminescent devices by use of Ionic Liquids[J].Chem Mat,2005,17(12),3187-3190.
[36] Slinker J D,Koh C Y,Malliaras G G,et al.Green electroluminescence from an ionic iridium complex[J].Appl Phys Lett,2005,86(17),173506.
[37] Tamayo A B,Garon S,Sajoto T,et al.Cationic bis-cyclometalated Iridium(III) diimine complexes and their use in efficient blue, green, and red electroluminescent devices[J].Inorg Chem,2005,44(24),8723-8732.
[38] Bolink H J,Cappelli L,Coronado E,et al.Stable single-layer light-emitting eElectrochemical cell using 4,7-diphenyl-1,10-phenanthroline-bis(2-phenylpyridine)iridium(III) hexafluorophosphate[J].J Am Chem Soc,2006,128(46),14786-14787.
[39] Bolink H J,Cappelli L,Coronado E,et al.Green light-emitting solid-state electrochemical cell obtained from a homoleptic Iridium(III) complex containing ionically charged ligands[J].Chem Mat, 2006,18(12),2778-2780.
[40] Nazeeruddin M K,Wegh R T,Zhou Z,et al.Efficient green-blue-light-emitting cationic iridium complex for light-emitting electrochemical cells[J].Inorg.Chem,2006,45(23),9245-9250.
[41] Su H C,Fang F C,Wong K T,et al.Efficient solid-state host-guest light-emitting electrochemical cells based on cationic transition metal complexes[J].Appl Phys Lett,2006,89(26),261118.
[42] Su H C,Fang F C,Chen H F,et al.Highly efficient orange and green solid-state light-emitting electrochemical cells based on cationic Ir(III) complexes with enhanced steric hindrance[J].Adv Funct Mater,2007,17(6),1019-1027.
[43] Zeng X S,Tavasli M,Perepichka I E,et al.Cationic bis-cyclometallated Iridium(III) phenanthroline complexes with pendant fluorenyl substituents:synthesis,redox,photophysical properties and light-emitting cells[J].Chem–Eur J,2008,14,933-943.
[44] Slinker J D,Parker J B,Malliaras G G,et al.Improved turn-on times of light-emitting electrochemical cells[J].Chem Mat,2008,20,388-396.
[45] Zhang Q S,Cheng Y X,Wang L X,et al .Highly efficient electroluminescence from green-light-emitting electrochemical cells based on Cu(I) complexes[J].Adv Funct Mater,2006,16(9),1203-1208.
[46] Bernhard S,Gao X C,Malliaras G G,et al.Efficient electroluminescent devices based on a chelatedosmium(II) complex[J].Adv Mater,2002,14(6),433.
[47] deMello J C . Interfacial feedback dynamics in polymer light-emitting electrochemical cells[J].Physical Review B,2002,66,235210.
[48] Bernhard S,Gao X,Malliaras G G,et al.Efficient electroluminescent devices based on a chelated osmium(II) complex[J].Adv Mater,2002,14,433–436.
[49] Gorodetsky A A,Parker S,Slinker J D,et al.Contact issues in electroluminescent devices from ruthenium complexes[J].Appl Phys Lett,2004,84,807–809.
[50] Pei Q B,Yu G,Zhang C,et al.Science,1995,269,1086–1088.
[51] Holder E,Schubert U S.New trends in the use of transition metal-ligand complexes for applications in electroluminescent devices[J].Adv Mater,2005,17,1109–1121.
[52] Lee J K,Yoo D S,Handy E S,et al.Thin film light emitting devices from an electroluminescent ruthenium complex [J].Appl Phys Lett,1996,69(12),1686-1688.
[53] Rudmann H,Shimada S,Rubner M F.Solid-state light-emitting devices based on the tris-chelated ruthenium(II) complex : high-efficiency light-emitting devices based on derivatives of the tris(2,2‘-bipyridyl) ruthenium(II) complex [J].J Am Chem Soc,2002,124(17),4918-4921.
[54] Liu C Y , Bard A J . Highly efficient and bright electroluminescent Ru(bpy)3(ClO4)2/Alq3 device[J].Appl Phys Lett,2005,87(6),61110.
[55] Su H C,Wu C C,Fang F C,et al.Efficient solid-state host-guest light-emitting electrochemical cells based on cationic transition metal complexes[J].Appl Phys Lett,2006,89(26),261118.
[56] Slinker J D,Gorodetsky A A,Wang J j,et al.Efficient yellow electroluminescence from a single layer of a cyclometalated iridium complex[J].J. Am. Chem. Soc,2004,126 (9),2763–2767.
[57] Plummer,Dijken E A,Cola H W,et al.Electrophosphorescent devices based on cationic complexes: control of switch-on voltage and efficiency through modification of charge Injection and charge transport[J].Adv Funct Mater,2005,15 (2),281-289.
[58] Slinker J D,Koh C Y,Malliaras G G,et al.Green electroluminescence from an ionic iridium complex[J].Appl Phys Lett,2005,86(17),173506-1-173506-3.
[59] Lowry M S,Slinker J D,Stefan Bernhard,et al.Single-layer electroluminescent devices and photoinduced hydrogen production from an Ionic Iridium(III) complex[J].Chem Mater,2005,17 (23),5712–5719.
[60] Thompson M E,Tamayo A B,Garon S,et al.Cationic bis-cyclometalated iridium(III) diimine complexes and their use in efficient blue, green, and red electroluminescent devices[J].Inorg Chem,2005,44(24),8723–8732.
[61] Zhang Q S,ZhouQ G,Wang L X,et al.Highly efficient electroluminescence from green-light-emitting electrochemical cells based on Cu(I) complexes[J].Adv Funct Mater,2006,16(9),1203-1208.
[62] Wong K T,Wu C C,Su H C,et al.Highly efficient orange and green solid-state light-emitting electrochemical cells based on cationic IrIII complexes with enhanced steric hindrance[J].Adv Funct Mater,2007,1019一1027.
[63] Qiu Y , He L , Duan L , et al . Blue-emitting cationic iridium complexes with 2-(1H-Pyrazol-1-yl)pyridine as the ancillary ligand for efficient light-emitting electrochemical cells[J].Adv Funct Mater.2008,18,2123一2131.
[64] Liu C Y,Bard A J.Increased photo and electroluminescence by zone annealing of spin-coated and vacuum-sublimed amorphous films producing crystalline thin films [J].Appl Phys Lett,2003,83,5431–5433.
[65] Liu C Y , Bard A J , Highly efficient and bright electroluminescent Ru(bpy)3(ClO4)2/Alq3 device[J].Appl Phys Lett,2005,87,61110.
[66] Lee K W,Slinker J D,Gorodetsky A A,et al. Phys Chem Chem Phys,2003,5,2706–2709.
[67] Su H C,Fang F C,Chen H F,et al.Highly efficient orange and green solid-state light-emitting electrochemical cells based on cationic ir(III) complexes with enhanced steric hindrance[J].Adv Funct Mater,2007,17,1019–1027.
[68] Zhang Q,Zhou Q,Cheng Y,et al.Highly efficient electroluminescence from green-light-emitting electrochemical cells based on Cu(I) complexes[J].Adv Funct Mater,2006,16,1203–1208.
[69] Hong J I,Kwon T H,Yong H O,et al.New approach toward fast response light-emitting electrochemical cells based on neutral iridium complexes via cation transport[J].Adv Funct Mater,2009,19,711–717.
[70] Wang J F,Jabbour G E,Kippelen B,et al.Oxadiazole metal complex for organic light-emitting diodes[J].Adv.Mater,1999,11(15),1266-1269.
[71] Xu zhaowu,Li yang,Ma xuemei,et al.Synthesis and properties of iridium complexes based 1,3,4-oxadiazoles derivatives[J].Tetrahedron,2008,64(8),1860-1867.
[72] Repetto D,Bolink H J,Housecroft C E,et al.A supramolecularly-caged ionic iridium(III) complex yielding bright and very stable solid-state light-emitting electrochemical cells[J].J Am Chem Soc, 2008,130,14944-14945.
[73] Shihuahong,Caoyong,Zhangxiuju,et al.New iridium complex as high-efficiency red phosphorescent emitter in polymer light-emitting devices[J].J Mater Chem,2006,16(13),1281-1286.
[74] Naso F,Cola L D,Babudri F,Blue emitting iridium complexes:synthesis,photophysics and phosphorescent devices[J].J Mater Chem2006,16,1161-1170.
[75] Wong K T,Wu C C,Su H C,et al.Highly efficient orange and green solid-state light-emitting electrochemical cells based on cationic Ir(III) complexes with enhanced steric hindrance[J].Adv.Funct.Mater,2007,17,1019-1027.
[76] Bolink H J,li L C,Coronado E,et al.Stable single-layer light-emitting electrochemical cell using 4,7-diphenyl-1,10-phenanthroline-bis(2-phenylpyridine)iridium(III) Hexafluorophosphate[J].J Am Chem Soc,2006,128,14786-14787.
[77] Bolink H J,Coronado E,Costa R D,et al.Near-quantitative internal quantum efficiency in a light-emitting electrochemical cell[J].Inorg Chem,2008,47(20),9149-9151.
[78] Bolink H J,Grtzel M,Nazeeruddin M K,et al.Controlling phosphorescence color and quantum yieldsin cationic iridium complexes:A combined experimental and theoretical study[J].Inorg Chem, 2007,46 (15),5989-6001.
[79] Parker S T,Slinker J D,Lowry M S,et al.Improved turn-on times of iridium electroluminescent devices by use of ionic liquids[J].Chem Mater,2005,17,3187.
[80] Wong K T,Wu C C,Su H C,et al.Highly efficient orange and green solid-state light-emitting electrochemical cells based on cationic ir(III) complexes with enhanced steric hindrance[J].Adv Funct Mater,2007,17,1019-1027.
[81] Edman L,Pauchard M,Moses D,et al.Planar polymer light-emitting device with fast kinetics at a low voltage[J].J Appl Phys,2004,95,4357.
[82] Wenzl F P,Pachler P,Suess C,et al.The Influence of the phase morphology on the optoelectronic properties of light-emitting electrochemical cells[J].Adv Funct Mater,2004,14(5),441.
[83] Bolink H J,Housecroft C E,et al.A supramolecularly-caged ionic iridium(III) complex yielding bright and very stable solid-state light-emitting electrochemical cells[J].J Am Chem Soc,2008,130,14944-14945.
[84] Hong J I,Kwon T H,Shin I S,et al.New Approach Toward Fast Response Light-Emitting Electrochemical cells based on neutral iridium complexes via cation transport[J].Adv Funct Mater,2009,19(5),711–717.
[2] Gorodetsky A A,Parker S,Slinker J D,et al.Contact issues in electroluminescent devices from ruthenium complexes[J].Applied Physics Letters,2004,84,807–809.
[3] Holder E,Langeveld B M,Schubert U S,et al.New trends in the use of transition metal-ligand complexes for applications in electroluminescent devices[J].Advanced Material,2005,17,1109–1121.
[4] Slinker J D,Parker J B,Abru?a H D,et al.Electroluminescent devices from ionic transition metal complexes[J].Journal of Material Chemistry,2007,17,2976–2988.
[5] Pope M, Kallmann H P,Magnante P,et al.Electroluminescence in organic crystals[J].J Chem Phys, 1963,38(8),2042-2043.
[6] Vincett P S,Barlow W A,Hann R A,et al.Eectrical conduction and low voltage blue electroluminescence in vacuum-deposited organic film[J].Thin Solid Films,1982,94,171.
[7] Gau E J,Macdiarmjol S C,Physical Review Letters,1977,39,1098.
[8] Tang C W,Vanslyke S A,et al.Organic eletrouminescenec diodes[J].Applied Physics Letters,1987, 51(12),913.
[9] Pei Q B,Yu G,Yang Y,et al.Polymer light-emitting electrochemical-cells[J].Science,1995, 269,1086–1088.
[10] Lee J,Chu H Y,Do L M,et al.High efficiency organic light-emitting devices with Al/NaF cathode[J].Appl Phys Lett,2003,82(2),173-175.
[11] Pei Q B,Yang Y,Zhang C,et al.Polymer light-emitting electrochemical cells:In situ formation of a light-emitting p?n junction[J].J Am Chem Soc ,1996,118(16),3922-3929.
[12] Ouisse T,Armand M,Kervella Y,et al.Fully transparent organic light-emitting electrochemical cells[J].Appl Phys Lett.2002,81(17),3131-3133.
[13] Lyons C H,Abbas E D,Lee J K,et al.Solid-state light-emitting devices based on the trischelated ruthenium(II) complex[J].J Am Chem Soc,1998,120(46),12100-12107.
[14] Handy E S,Pal A J,Rubner M F.Solid-state light-emitting devices based on the tris-chelated ruthenium(II) complex as a high-brightness emitter[J].J Am Chem Soc,1999,121(14),3525-3528.
[15] Wu A,Yoo D,Lee J K,et al.Solid-state light-emitting devices based on the tris-chelated ruthenium(II) complex:high efficiency devices via a layer-by-Layer molecular-level blending approach[J].J Am Chem Soc,1999,121(20),4883-4891.
[16] Gao F G , Bard A J , Solid-state organic light-Emitting diodes based on Tris(2,2‘-bipyridine)ruthenium(II) complexes[J].J Am Chem Soc.2000,122(30),7426-7427.
[17] Rudmann H,Rubner M F.Single layer light-emitting devices with high efficiency and long lifetime based on tris(2,2′-bipyridyl) ruthenium(II) hexafluorophosphate[J].J Appl Phys,2001,90(9),4338-4345.
[18] Bernhard S,Barron J A,Houston P L,et al.Electroluminescence in ruthenium(II) complexes[J].J Am Chem Soc,2002,124(45),13624-13628.
[19] Buda M,Kalyuzhny G,Bard A J,Thin-film solid-state electroluminescent devices based onTris(2,2′-bipyridine) ruthenium(II) complexes[J].J.Am Chem Soc,2002,124(21),6090-6098.
[20] Gao F G,Bard A. J.High-brightness and low-voltage light-emitting devices based on trischelated ruthenium(II) and tris(2,2‘-bipyridine) osmium(II) emitter layers and low melting point alloy cathode contacts[J].Chem Mat,2002,14(8),3465-3470.
[21] Lepretre J C,Deronzier A,Stephan O,Light-emitting electrochemical cells based on ruthenium(II) using crown ether as solid electrolyte [J].Syn Met,2002,131(1-3),175-183.
[22] Rudmann H,Shimada S,Rubner M F,et al.Solid-state light-emitting devices based on the tris-chelated ruthenium(II) complex:.high-efficiency light-emitting devices based on derivatives of the tris(2,2‘-bipyridyl) ruthenium(II) complex[J].J Am Chem Soc,2002,124(17),4918-4921.
[23] Rudmann H,Shimada S,Rubner M F,et al.Prevention of the cathode induced electrochemical degradation of [Ru(bpy)3](PF6)2 light emitting devices[J].J Appl Phys,2002,92(3),1576-1581.
[24] Kalyuzhny G,Buda M,McNeill J,et al.Stability of thin-film solid-state electroluminescent devices based on tris(2,2‘-bipyridine)ruthenium(II) complexes[J].J.Am.Chem.Soc,2003,125(20), 6272-6283.
[25] Rudmann H,Shimada S,Rubner M F.Operational mechanism of light-emitting devices based on Ru(II) complexes:Evidence for electrochemical junction formation[J].J Appl Phys.2003,94(1),115-122.
[26] Slinker J D,Houston P L,Abruna H D,et al.Solid-state electroluminescent device based on transition metal complexes[J].Chem Commun,2003,(19),2392-2399.
[27] Yang J H , Gordon K C , Zidon Y , et al . Light-emitting devices based on ruthenium(II)(4,7-diphenyl-1,10-phenanthroline)3:Device response rate and efficiency by use of tris-(8-hydroxyquinoline) aluminum[J].J Appl Phys,2003,94(10),6391-6395.
[28] Chuai Y T,Lee D N,Zhen C G,et al.Novel polypyridyl ruthenium(II) complexes for electroluminescence [J].Syn Met,2004,145(2-3),259-264.
[29] Gorodetsky A A,Parker S,Slinker J D,et al.Contact issues in electroluminescent devices from ruthenium complexes[J].Appl Phys Lett,2004,84(5),807-809.
[30] Liu C Y , Bard A J . Highly efficient and bright electroluminescent Ru(bpy)3(ClO4)2/Alq3 device[J].Appl Phys Lett,2005,87(6),61110.
[31] Pile D L , Bard A J . Effect of water vapor on the operation and stability of tris(2,2‘-bipyridine)ruthenium(II)-Based light-emitting electrochemical cells [J].Chem Mat,2005,17(16),4212-4217.
[32] Zhao W,Liu C Y,Wang Q,et al.Effect of residual solvent on ru(bpy)3(ClO4)2-based light-emitting electrochemical cells[J].Chem Mat.2005,17(25),6403-6406.
[33] Bolink H J,Cappelli L,Coronado E,et al.Efficient and stable solid-state light-emitting electrochemical cell using tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) hexafluorophosphate[J].J Am Chem Soc,2006,128(1),46-47.
[34] Jia W L,Hu Y F,Gao J,et al.Linear and star-shaped polynuclear Ru(II) complexes of 2-(2′-pyridyl)benzimidazolyl derivatives:syntheses,photophysical properties and red light-emitting devices[J].Dalton Trans,2006,14,1721-1728.
[35] Parker S T,Slinker J D,Lowry M S,et al.Improved turn-on times of Iridium electroluminescent devices by use of Ionic Liquids[J].Chem Mat,2005,17(12),3187-3190.
[36] Slinker J D,Koh C Y,Malliaras G G,et al.Green electroluminescence from an ionic iridium complex[J].Appl Phys Lett,2005,86(17),173506.
[37] Tamayo A B,Garon S,Sajoto T,et al.Cationic bis-cyclometalated Iridium(III) diimine complexes and their use in efficient blue, green, and red electroluminescent devices[J].Inorg Chem,2005,44(24),8723-8732.
[38] Bolink H J,Cappelli L,Coronado E,et al.Stable single-layer light-emitting eElectrochemical cell using 4,7-diphenyl-1,10-phenanthroline-bis(2-phenylpyridine)iridium(III) hexafluorophosphate[J].J Am Chem Soc,2006,128(46),14786-14787.
[39] Bolink H J,Cappelli L,Coronado E,et al.Green light-emitting solid-state electrochemical cell obtained from a homoleptic Iridium(III) complex containing ionically charged ligands[J].Chem Mat, 2006,18(12),2778-2780.
[40] Nazeeruddin M K,Wegh R T,Zhou Z,et al.Efficient green-blue-light-emitting cationic iridium complex for light-emitting electrochemical cells[J].Inorg.Chem,2006,45(23),9245-9250.
[41] Su H C,Fang F C,Wong K T,et al.Efficient solid-state host-guest light-emitting electrochemical cells based on cationic transition metal complexes[J].Appl Phys Lett,2006,89(26),261118.
[42] Su H C,Fang F C,Chen H F,et al.Highly efficient orange and green solid-state light-emitting electrochemical cells based on cationic Ir(III) complexes with enhanced steric hindrance[J].Adv Funct Mater,2007,17(6),1019-1027.
[43] Zeng X S,Tavasli M,Perepichka I E,et al.Cationic bis-cyclometallated Iridium(III) phenanthroline complexes with pendant fluorenyl substituents:synthesis,redox,photophysical properties and light-emitting cells[J].Chem–Eur J,2008,14,933-943.
[44] Slinker J D,Parker J B,Malliaras G G,et al.Improved turn-on times of light-emitting electrochemical cells[J].Chem Mat,2008,20,388-396.
[45] Zhang Q S,Cheng Y X,Wang L X,et al .Highly efficient electroluminescence from green-light-emitting electrochemical cells based on Cu(I) complexes[J].Adv Funct Mater,2006,16(9),1203-1208.
[46] Bernhard S,Gao X C,Malliaras G G,et al.Efficient electroluminescent devices based on a chelatedosmium(II) complex[J].Adv Mater,2002,14(6),433.
[47] deMello J C . Interfacial feedback dynamics in polymer light-emitting electrochemical cells[J].Physical Review B,2002,66,235210.
[48] Bernhard S,Gao X,Malliaras G G,et al.Efficient electroluminescent devices based on a chelated osmium(II) complex[J].Adv Mater,2002,14,433–436.
[49] Gorodetsky A A,Parker S,Slinker J D,et al.Contact issues in electroluminescent devices from ruthenium complexes[J].Appl Phys Lett,2004,84,807–809.
[50] Pei Q B,Yu G,Zhang C,et al.Science,1995,269,1086–1088.
[51] Holder E,Schubert U S.New trends in the use of transition metal-ligand complexes for applications in electroluminescent devices[J].Adv Mater,2005,17,1109–1121.
[52] Lee J K,Yoo D S,Handy E S,et al.Thin film light emitting devices from an electroluminescent ruthenium complex [J].Appl Phys Lett,1996,69(12),1686-1688.
[53] Rudmann H,Shimada S,Rubner M F.Solid-state light-emitting devices based on the tris-chelated ruthenium(II) complex : high-efficiency light-emitting devices based on derivatives of the tris(2,2‘-bipyridyl) ruthenium(II) complex [J].J Am Chem Soc,2002,124(17),4918-4921.
[54] Liu C Y , Bard A J . Highly efficient and bright electroluminescent Ru(bpy)3(ClO4)2/Alq3 device[J].Appl Phys Lett,2005,87(6),61110.
[55] Su H C,Wu C C,Fang F C,et al.Efficient solid-state host-guest light-emitting electrochemical cells based on cationic transition metal complexes[J].Appl Phys Lett,2006,89(26),261118.
[56] Slinker J D,Gorodetsky A A,Wang J j,et al.Efficient yellow electroluminescence from a single layer of a cyclometalated iridium complex[J].J. Am. Chem. Soc,2004,126 (9),2763–2767.
[57] Plummer,Dijken E A,Cola H W,et al.Electrophosphorescent devices based on cationic complexes: control of switch-on voltage and efficiency through modification of charge Injection and charge transport[J].Adv Funct Mater,2005,15 (2),281-289.
[58] Slinker J D,Koh C Y,Malliaras G G,et al.Green electroluminescence from an ionic iridium complex[J].Appl Phys Lett,2005,86(17),173506-1-173506-3.
[59] Lowry M S,Slinker J D,Stefan Bernhard,et al.Single-layer electroluminescent devices and photoinduced hydrogen production from an Ionic Iridium(III) complex[J].Chem Mater,2005,17 (23),5712–5719.
[60] Thompson M E,Tamayo A B,Garon S,et al.Cationic bis-cyclometalated iridium(III) diimine complexes and their use in efficient blue, green, and red electroluminescent devices[J].Inorg Chem,2005,44(24),8723–8732.
[61] Zhang Q S,ZhouQ G,Wang L X,et al.Highly efficient electroluminescence from green-light-emitting electrochemical cells based on Cu(I) complexes[J].Adv Funct Mater,2006,16(9),1203-1208.
[62] Wong K T,Wu C C,Su H C,et al.Highly efficient orange and green solid-state light-emitting electrochemical cells based on cationic IrIII complexes with enhanced steric hindrance[J].Adv Funct Mater,2007,1019一1027.
[63] Qiu Y , He L , Duan L , et al . Blue-emitting cationic iridium complexes with 2-(1H-Pyrazol-1-yl)pyridine as the ancillary ligand for efficient light-emitting electrochemical cells[J].Adv Funct Mater.2008,18,2123一2131.
[64] Liu C Y,Bard A J.Increased photo and electroluminescence by zone annealing of spin-coated and vacuum-sublimed amorphous films producing crystalline thin films [J].Appl Phys Lett,2003,83,5431–5433.
[65] Liu C Y , Bard A J , Highly efficient and bright electroluminescent Ru(bpy)3(ClO4)2/Alq3 device[J].Appl Phys Lett,2005,87,61110.
[66] Lee K W,Slinker J D,Gorodetsky A A,et al. Phys Chem Chem Phys,2003,5,2706–2709.
[67] Su H C,Fang F C,Chen H F,et al.Highly efficient orange and green solid-state light-emitting electrochemical cells based on cationic ir(III) complexes with enhanced steric hindrance[J].Adv Funct Mater,2007,17,1019–1027.
[68] Zhang Q,Zhou Q,Cheng Y,et al.Highly efficient electroluminescence from green-light-emitting electrochemical cells based on Cu(I) complexes[J].Adv Funct Mater,2006,16,1203–1208.
[69] Hong J I,Kwon T H,Yong H O,et al.New approach toward fast response light-emitting electrochemical cells based on neutral iridium complexes via cation transport[J].Adv Funct Mater,2009,19,711–717.
[70] Wang J F,Jabbour G E,Kippelen B,et al.Oxadiazole metal complex for organic light-emitting diodes[J].Adv.Mater,1999,11(15),1266-1269.
[71] Xu zhaowu,Li yang,Ma xuemei,et al.Synthesis and properties of iridium complexes based 1,3,4-oxadiazoles derivatives[J].Tetrahedron,2008,64(8),1860-1867.
[72] Repetto D,Bolink H J,Housecroft C E,et al.A supramolecularly-caged ionic iridium(III) complex yielding bright and very stable solid-state light-emitting electrochemical cells[J].J Am Chem Soc, 2008,130,14944-14945.
[73] Shihuahong,Caoyong,Zhangxiuju,et al.New iridium complex as high-efficiency red phosphorescent emitter in polymer light-emitting devices[J].J Mater Chem,2006,16(13),1281-1286.
[74] Naso F,Cola L D,Babudri F,Blue emitting iridium complexes:synthesis,photophysics and phosphorescent devices[J].J Mater Chem2006,16,1161-1170.
[75] Wong K T,Wu C C,Su H C,et al.Highly efficient orange and green solid-state light-emitting electrochemical cells based on cationic Ir(III) complexes with enhanced steric hindrance[J].Adv.Funct.Mater,2007,17,1019-1027.
[76] Bolink H J,li L C,Coronado E,et al.Stable single-layer light-emitting electrochemical cell using 4,7-diphenyl-1,10-phenanthroline-bis(2-phenylpyridine)iridium(III) Hexafluorophosphate[J].J Am Chem Soc,2006,128,14786-14787.
[77] Bolink H J,Coronado E,Costa R D,et al.Near-quantitative internal quantum efficiency in a light-emitting electrochemical cell[J].Inorg Chem,2008,47(20),9149-9151.
[78] Bolink H J,Grtzel M,Nazeeruddin M K,et al.Controlling phosphorescence color and quantum yieldsin cationic iridium complexes:A combined experimental and theoretical study[J].Inorg Chem, 2007,46 (15),5989-6001.
[79] Parker S T,Slinker J D,Lowry M S,et al.Improved turn-on times of iridium electroluminescent devices by use of ionic liquids[J].Chem Mater,2005,17,3187.
[80] Wong K T,Wu C C,Su H C,et al.Highly efficient orange and green solid-state light-emitting electrochemical cells based on cationic ir(III) complexes with enhanced steric hindrance[J].Adv Funct Mater,2007,17,1019-1027.
[81] Edman L,Pauchard M,Moses D,et al.Planar polymer light-emitting device with fast kinetics at a low voltage[J].J Appl Phys,2004,95,4357.
[82] Wenzl F P,Pachler P,Suess C,et al.The Influence of the phase morphology on the optoelectronic properties of light-emitting electrochemical cells[J].Adv Funct Mater,2004,14(5),441.
[83] Bolink H J,Housecroft C E,et al.A supramolecularly-caged ionic iridium(III) complex yielding bright and very stable solid-state light-emitting electrochemical cells[J].J Am Chem Soc,2008,130,14944-14945.
[84] Hong J I,Kwon T H,Shin I S,et al.New Approach Toward Fast Response Light-Emitting Electrochemical cells based on neutral iridium complexes via cation transport[J].Adv Funct Mater,2009,19(5),711–717.