铂铱双核环金属配合物电致磷光材料的合成及其性能研究
|
摘要
本论文综述了有机电致磷光材料及其白光有机电致发光器件的发展历程和研究现状。针对目前单分子电致白光材料品种少,其单掺杂单发光层聚合物电致白光器件发光效率低、色度稳定性差等问题,开展了铂铱双核环金属配合物磷光材料的合成及其热稳定性,光物理性能,电化学性能和电致发光性能的研究,主要研究结果如下:
1.利用双吡啶-2-甲酸阴离子配体(pic-pic)和单阴离子配体-C^N环金属配体(pic-ppy)等两类桥联方式,构筑了二个系列的铂铱双核环金属配合物磷光材料,并通过Vilsmeirer-Haack甲酰化反应、Suzuki-Miyaura交叉偶联反应和Williamson成醚反应等合成得到了这些铂铱双核环金属配合物。
2.二类铂铱双核环金属配合物的热分解温度在261 ~ 292℃,与对应单核环金属铱配合物的热分解温度(260℃)相比,这些双核环金属配合物具有较高的热稳定性能。
3.二类铂铱双核环金属配合物的二氯甲烷溶液在255 nm左右显示了很强的配体-配体电荷转移(LLCT)的π-π*电子跃迁吸收,在374 nm左右有较弱的金属-配体电荷转移(MLCT)的π-π*电子跃迁吸收。载流子传输基团的引入大大增强了双核环金属配合物的LLCT吸收。与对应单核环金属铂配合物的紫外吸收光谱相比,二类铂铱双核环金属配合物在328 nm附近的金属-金属-配体电荷转移(MMLCT)的电子跃迁吸收消失。
4.二类铂铱双核环金属配合物在二氯甲烷溶液中呈现了相似的发光光谱,最大发射峰和肩峰分别位于469 ~ 481 nm和495 ~ 505 nm处。其中,pic-pic型铂铱双核环金属配合物与pic-ppy型铂铱双核环金属配合物相比,溶液发光光谱约有7nm的蓝移。值得注意的是,二类铂铱双核环金属配合物在固体膜中,呈现了显著不同的发光光谱。pic-pic型铂铱双核环金属配合物没有发生聚集态的发光,但pic-ppy型铂铱双核环金属配合物在609 ~ 658 nm显示了强烈的聚集态发光。这说明通过不同的桥联方式,可以调控铂铱双核环金属配合物的聚集态的形成。
5.二类铂铱双核环金属配合物的最高占领分子轨道的能级(E_(HOMO))在-5.51-6.06 eV之间,最低未占领分子轨道的能级(E_(LUMO))在-3.08-3.20 eV之间。与相应的单核环金属铂配合物相比,二类铂铱双核环金属配合物呈现了升高的E_(HOMO)和E_(LUMO)。
6.以铂铱双核环金属配合物为客体材料,聚乙烯咔唑为主体材料制作了单掺杂单发光层聚合物电致发光器件。当客体材料为1wt %FIr(pic)-C_6OXDC_6 -FPt(pic)时,器件在14 V电压下,获得了色坐标为(0.33, 0.38)的近白光发射。当配合物FIr(pic)-C_6-FPt(pic)的掺杂浓度增加到8 wt %时,器件的最大的亮度为935 cd m~(-2),最大的电流效率为1.24 cd A~(-1)。
本论文工作为进一步开展双核及多核环金属配合物电致白光材料的合成及其性能研究打下了基础,同时为了进一步获得具有良好的稳定性和高效率的单掺杂白光聚合物电致发光器件起到了积极的推动作用。
The development and status of organic electrophosphorescent materials and white organic light-emitting devices (WOLEDs) were reviewed in this dissertation. In order to solve the problems, such as scarce single white-emitting organic materials, low luminescent efficiency and bad chroma stability for the devices, we designed and synthesized two classes of dinuclear platinum-iridium complexes, as well as study their thermal, photophysical, electrochemical and electroluminescent properties. The key results are listed as followed.
1. Two classes of dinuclear platinum-iridium complexes were designed by two connected ways of the bi(picolinic acid) anion ligand (pic-pic) and the anion-C^N cyclometalated ligand (pic-ppy). These platinum-iridium dinuclear complexes were synthesized by a series of reactions, such as Vilsmeirer-Haack reaction, Miyaura- Suzuki coupling reaction and Williamson ether-forming reaction.
2. The decomposed temperatures were about 261 ~ 292℃for these dinuclear platinum -iridium complexes. Compared to iridium(Ⅲ) di(4,6-difluophenyl pyridinate-C~2,N) (picolinate) [FIr(pic)], these dinuclear platinum-iridium complexes presented better thermal stability.
3. These dinuclear platinum-iridium complexes exhibited as an intense absorption band about 255 nm from the ligand-to-ligand charge transfer (LLCT) transition and a weak absorption band about 374 nm from the metal-to-ligand charge transfer (MLCT) transition. Introduction of carrier-transporting group into the complexes is available to enhance the LLCT absorption for these dinuclear platinum-iridium complexes. Compared to platinum (Ⅱ) (4,6-difluophenyl pyridinate-C~2,N) (picolinate) [FPt(pic)], None of these platinum-iridium complexes displayed the absorption band about 328 nm from metal-to-metal-to-ligand charge transfer (MMLCT) transition.
4. All these complexes gave a nearly identical photoluminescence (PL) spectrum in dichloromethane (DCM). The maximum emission peak at 469 ~ 481 nm with a shoulder at 495 ~ 505 nm was observed. Compared to the pic-ppy-based dinuclear platinum-iridium complexes, the pic-pic-based ones presented 7 nm blue-shifted PL spectra. It is noted that two classes of dinuclear platinum-iridium complexes showed different PL spectra in their neat films. None of the pic-pic-based ones presented excimer emission. However, all of the pic-ppy-based ones displayed strong excimer emission about 609 ~ 658 nm. This indicates that the formation of molecular aggrega- tion state can be effectively tuned by different connected ways.
5. The highest occupied molecular orbital energy levels (E_(HOMO)) were in the range of -5.51 ~ -6.06 eV,and the lowest unoccupied molecular orbital energy levels (E_(LUMO)) were around -3.08 ~ -3.20 eV for these dinuclear platinum-iridium complexes. Compared to FPt(pic), these dinuclear platinum-iridium complexes presented higher E_(HOMO) and E_(LUMO).
6. The single-layer polymer light-emitting devices (PLEDs) were fabricated by using these dinuclear platinum-iridium complexes as dopants and poly(vinyl-carbazole) (PVK) as host matrix. While the dinuclear platinum-iridium complex of FIr(pic)- C_6OXDC_6-FPt(pic) was used as a single doapnt, the device exhibited near-white emission with a CIE coordinate (0.33, 0.38) at a 1% doping concentration and a applied voltages of 14V. The dinuclear platinum-iridium complex of FIr(pic)- C_6-FPt(pic) at 8% doping concentration, the device presented the maximal luminance of 935 cd m~(-2) and current efficiency of 1.24 cd A~(-1), respectively.
This investigation has laid a well foundation for further study on the dinuclear and multi-nuclear complexes used as white-emitting organic materials. It may promote the development of the white-emiting PLEDs with high stability and efficiency.
1.利用双吡啶-2-甲酸阴离子配体(pic-pic)和单阴离子配体-C^N环金属配体(pic-ppy)等两类桥联方式,构筑了二个系列的铂铱双核环金属配合物磷光材料,并通过Vilsmeirer-Haack甲酰化反应、Suzuki-Miyaura交叉偶联反应和Williamson成醚反应等合成得到了这些铂铱双核环金属配合物。
2.二类铂铱双核环金属配合物的热分解温度在261 ~ 292℃,与对应单核环金属铱配合物的热分解温度(260℃)相比,这些双核环金属配合物具有较高的热稳定性能。
3.二类铂铱双核环金属配合物的二氯甲烷溶液在255 nm左右显示了很强的配体-配体电荷转移(LLCT)的π-π*电子跃迁吸收,在374 nm左右有较弱的金属-配体电荷转移(MLCT)的π-π*电子跃迁吸收。载流子传输基团的引入大大增强了双核环金属配合物的LLCT吸收。与对应单核环金属铂配合物的紫外吸收光谱相比,二类铂铱双核环金属配合物在328 nm附近的金属-金属-配体电荷转移(MMLCT)的电子跃迁吸收消失。
4.二类铂铱双核环金属配合物在二氯甲烷溶液中呈现了相似的发光光谱,最大发射峰和肩峰分别位于469 ~ 481 nm和495 ~ 505 nm处。其中,pic-pic型铂铱双核环金属配合物与pic-ppy型铂铱双核环金属配合物相比,溶液发光光谱约有7nm的蓝移。值得注意的是,二类铂铱双核环金属配合物在固体膜中,呈现了显著不同的发光光谱。pic-pic型铂铱双核环金属配合物没有发生聚集态的发光,但pic-ppy型铂铱双核环金属配合物在609 ~ 658 nm显示了强烈的聚集态发光。这说明通过不同的桥联方式,可以调控铂铱双核环金属配合物的聚集态的形成。
5.二类铂铱双核环金属配合物的最高占领分子轨道的能级(E_(HOMO))在-5.51-6.06 eV之间,最低未占领分子轨道的能级(E_(LUMO))在-3.08-3.20 eV之间。与相应的单核环金属铂配合物相比,二类铂铱双核环金属配合物呈现了升高的E_(HOMO)和E_(LUMO)。
6.以铂铱双核环金属配合物为客体材料,聚乙烯咔唑为主体材料制作了单掺杂单发光层聚合物电致发光器件。当客体材料为1wt %FIr(pic)-C_6OXDC_6 -FPt(pic)时,器件在14 V电压下,获得了色坐标为(0.33, 0.38)的近白光发射。当配合物FIr(pic)-C_6-FPt(pic)的掺杂浓度增加到8 wt %时,器件的最大的亮度为935 cd m~(-2),最大的电流效率为1.24 cd A~(-1)。
本论文工作为进一步开展双核及多核环金属配合物电致白光材料的合成及其性能研究打下了基础,同时为了进一步获得具有良好的稳定性和高效率的单掺杂白光聚合物电致发光器件起到了积极的推动作用。
The development and status of organic electrophosphorescent materials and white organic light-emitting devices (WOLEDs) were reviewed in this dissertation. In order to solve the problems, such as scarce single white-emitting organic materials, low luminescent efficiency and bad chroma stability for the devices, we designed and synthesized two classes of dinuclear platinum-iridium complexes, as well as study their thermal, photophysical, electrochemical and electroluminescent properties. The key results are listed as followed.
1. Two classes of dinuclear platinum-iridium complexes were designed by two connected ways of the bi(picolinic acid) anion ligand (pic-pic) and the anion-C^N cyclometalated ligand (pic-ppy). These platinum-iridium dinuclear complexes were synthesized by a series of reactions, such as Vilsmeirer-Haack reaction, Miyaura- Suzuki coupling reaction and Williamson ether-forming reaction.
2. The decomposed temperatures were about 261 ~ 292℃for these dinuclear platinum -iridium complexes. Compared to iridium(Ⅲ) di(4,6-difluophenyl pyridinate-C~2,N) (picolinate) [FIr(pic)], these dinuclear platinum-iridium complexes presented better thermal stability.
3. These dinuclear platinum-iridium complexes exhibited as an intense absorption band about 255 nm from the ligand-to-ligand charge transfer (LLCT) transition and a weak absorption band about 374 nm from the metal-to-ligand charge transfer (MLCT) transition. Introduction of carrier-transporting group into the complexes is available to enhance the LLCT absorption for these dinuclear platinum-iridium complexes. Compared to platinum (Ⅱ) (4,6-difluophenyl pyridinate-C~2,N) (picolinate) [FPt(pic)], None of these platinum-iridium complexes displayed the absorption band about 328 nm from metal-to-metal-to-ligand charge transfer (MMLCT) transition.
4. All these complexes gave a nearly identical photoluminescence (PL) spectrum in dichloromethane (DCM). The maximum emission peak at 469 ~ 481 nm with a shoulder at 495 ~ 505 nm was observed. Compared to the pic-ppy-based dinuclear platinum-iridium complexes, the pic-pic-based ones presented 7 nm blue-shifted PL spectra. It is noted that two classes of dinuclear platinum-iridium complexes showed different PL spectra in their neat films. None of the pic-pic-based ones presented excimer emission. However, all of the pic-ppy-based ones displayed strong excimer emission about 609 ~ 658 nm. This indicates that the formation of molecular aggrega- tion state can be effectively tuned by different connected ways.
5. The highest occupied molecular orbital energy levels (E_(HOMO)) were in the range of -5.51 ~ -6.06 eV,and the lowest unoccupied molecular orbital energy levels (E_(LUMO)) were around -3.08 ~ -3.20 eV for these dinuclear platinum-iridium complexes. Compared to FPt(pic), these dinuclear platinum-iridium complexes presented higher E_(HOMO) and E_(LUMO).
6. The single-layer polymer light-emitting devices (PLEDs) were fabricated by using these dinuclear platinum-iridium complexes as dopants and poly(vinyl-carbazole) (PVK) as host matrix. While the dinuclear platinum-iridium complex of FIr(pic)- C_6OXDC_6-FPt(pic) was used as a single doapnt, the device exhibited near-white emission with a CIE coordinate (0.33, 0.38) at a 1% doping concentration and a applied voltages of 14V. The dinuclear platinum-iridium complex of FIr(pic)- C_6-FPt(pic) at 8% doping concentration, the device presented the maximal luminance of 935 cd m~(-2) and current efficiency of 1.24 cd A~(-1), respectively.
This investigation has laid a well foundation for further study on the dinuclear and multi-nuclear complexes used as white-emitting organic materials. It may promote the development of the white-emiting PLEDs with high stability and efficiency.
引文
[1] Lamansky S, Djurovich P. Murphy D. Highly phosphorescent bis-cyclometalated iridiumcomplexes: synthesis, photophysical characterization, and use in organic light emitting diodes. [J].J. Am. Chem. Soc. 2001, 123, 4304-4312.
[2] Slamansky S, Djovid P, Murphy D L, Abdd R F, Thompson M E. Synthesis andcharacterization of phosphorescent cyclometalated Iridium complexes. [J]. Inorg. Chem. 2001, 40,1704-1711.
[3] (a)Li C L, Su Y J, Tao Y T, Liu R S. Yellow and red electrophosphors based on linkage isomersof iridium phenylisoquinoline complexes: Distinct behaviors in photophysical and electroluminanceproperties. [J]. Adv. Funct. Mater. 2005, 15, 387-395. (b) Nam S C, Park J H, Lee S K,Lee J, Shim H K, Park M J, Hwang D H, Jung B J. Saturated and efficient red light-emittingfluorene-based alternating polymers containing phenothiazine derivatives. [J]. Macromolecules.2006, 39, 177-183.
[4] Duan J P, Sun P P, Cheng C H. New iridium complexes as highly efficient orange-red emittersin organic light-emitting diodes. [J]. Adv. Mater. 2003, 15, 224-228.
[5] Jiang C Y, Yang W, Peng J B, Xiao S, Cao Y. High-efficiency, saturated red-phosphorescentpolymer light-emitting diodes based on conjugated and non-conjugated polymers doped with an Ircomplex. [J]. Adv. Mater. 2004, 16, 537-541.
[6] Song Y H, Yeh S J, Chen C T, Lee G H. Bright and efficient, non-doped, phosphorescentorganic red-light-emitting diodes bright and efficient, non-doped, phosphorescent organicred-light-emitting diodes. [J]. Adv. Funct. Mater. 2004, 14, 1221-1226.
[7] Huang W S, Liu J T, Chein C H, Sun S S, Tao Y .,Wen Y S. Highly phosphorescentbis-cyclometalated iridium complexes containing benzoimidazole-based ligands. [J]. Chem. Mater.2004, 16, 2480-2488.
[8] Lu W, Chan M C W, Zhu N, Che C M, Li C, Hui Z. Structral and spectroscopic studies onPt Pt andπ-πinteractions in luminescent multinuclear cyclometalated platinum (Ⅱ) homologuestethered by oligophosphine auxiliaries. [J]. J. Am. Chem. Soc. 2004, 126, 7639-7651.
[9] Chan S C, ChanM C W, Wang Y, Che C W, Cheung K K, Zhu N. Organic Light-emittingmaterialsBased on bis (a rylacetylide ) platinum (Ⅱ) complexes bearing substituted bipyridine andphenanthroline ligands: photo-and electroluminescence from 3MLCT excited states. [J]. J. Chem.Eur. 2001, 7, 1480-1490.
[10] Huertas S, Hissler M, McGarrah J E, Lachicotte J E, Eisenberg R. Syntheses and structuralcharacterization of luminescent platinum (Ⅱ) complexes containing di-tert-butylbipyridine andnew 1, 1-dithiolate ligands. [J]. Inorg. Chem. 2001, 40, 1183-1188.
[11] Pomestchenko I E, Luman C R, Hissler M, Ziessel R, Castellano F N. Room temperaturephosphorescence from a platinum (Ⅱ) diimine bis( pyrenylacetylide ) complex. [J]. Inorg. Chem.2003, 42, 1394 -1396.
[12] Anbalagan V, Srivastava T S. Spectral and photophysical properties of mono and dinuclear Pt (Ⅱ) and Pd (Ⅱ) complexes: An unusual emission behavior. [J].Polyhedron. 2004, 23, 3173-3183.
[13] Kato M, Okamura T, Yamamoto H, Ueyama N. Effects of the intramolecular NH hydrogen bond in mono-nuclear platinum (Ⅱ) and palladium (Ⅱ) complexes with 2, 2’-bipyridine and benzenethiol derivatives. [J]. Inorg. Chem. 2005, 44, 1966-1972.
[14] Brooks J, Babayan Y, Lamansky S, Djurovich P I, Bau R, Thompson M E. Synthesis and characterization of phosphorescent cyclometalated platinum Complexes. [J]. Inorg. Chem. 2002, 41, 3055-3066.
[15] Kavitha J, Chang S Y, Chi Y, Yu J K, Hu Y H, Chou P H, Peng S M, Lee G H, Tao Y T, Chien C H, Carty A J. In search of high-performance platinum (Ⅱ) phosphorescent materials for the fabrication of red electro-phosphorescent devices. [J]. Adv. Funct. Mater. 2005, 15, 223-229.
[16] Lai S W, Chan M C W, Cheung T C, Peng S M, Che C M. Probing d8-d8 interactions in luminescent mono- and binuclear cyclometalated platinum (Ⅱ) complexes of 6-Phenyl-2, 2′-bipyridines. [J]. Inorg. Chem. 1999, 38, 4046-4055.
[17] Lu W, Mi B X, Chan M C W, Hui Z, Zhu N, Lee S T, Che C M. [(C^N^N)Pt(C≡C)nR] (HC^N^N=6-aryl-2, 2′-bipyridine, n=1～4, R=aryl, SiMe3) as a new class of light-emitting materials and their applications in electrophosphorescent devices. [J]. Chem. Commun. 2002, 206-207.
[18] Lu W, Mi B X, Chan M C W, Hui Z, Che C M, Zhu N, Lee S T. Light-emitting tridentate cyclometalated platinum (Ⅱ) complexes containingσ-alkynyl auxiliaries: Tuning of photo and electrophosphorescence. [J]. J. Am. Chem. Soc. 2004, 126, 4958-4971.
[19] Williams J A G, Beeby A, Davies E S, Weinstein J A, Wilson C. An alternative route to highly luminescent platinum (Ⅱ) complexes: cyclometalation with N^C^N coordinating dipyridylb- enzene ligands. [J]. Inorg. Chem. 2003, 42, 8609-8611.
[20] Farley S. J., Rochester D. L., Thompson A. L., Howard J. A. K., Williams J. A. G. Controlling emission energy, Self-quenching and excimer formation in highly luminescent N^C^N- coordinated platinum (Ⅱ) complexes. [J]. Inorg. Chem. 2005, 44, 9690-9703.
[21] Sotoyama W, Satoh T, Sawatari N, Inoue H. Efficient organic light-emitting diodes with phosphorescent platinum complexes containing N^C^N-coordinating tridentate ligand. [J]. Appl. Phys. Lett. 2005, 86, 153505.
[22] Baldo M A, O’Brien D F, You Y, Shoustikov A, Sibley S, Thompson M E, Forrest S R. Highly efficient phosphorescent emission from organic electroluminescent devices. [J]. Nature. 1998, 395, 151-154.
[23] Kwong R C, Sibley S, Dubovoy T, Baldo M, Forrest S R, Thompson M E. Efficient, saturated red organic light emitting devices based on phosphorescent platinum (Ⅱ) porphyrins. [J]. Chem. Mater. 1999, 11, 3709-3713.
[24] Xiang H F, Chan S C, Wu K K Y, Che C M, Laib P T. High-efficiency red electrophosphores- cence based on neutral bis(pyrrole)-diimine platinum (Ⅱ) complex. [J]. Chem. Commun. 2005, 1408-1410.
[25] Lin Y Y, Chan S C, Chan M C W, Hou Y J, Zhu N, Che C M, Liu Y, Wang Y. Structural, photophysical,and electrophosphorescent properties of platinum (Ⅱ) complexes supported by tetradentate N2O2 Chelates. [J]. Chem. Eur. J. 2003, 9, 1263-1272.
[26] O’Brien D F, Baldo M A, Thompson M E, Forrest S R. Improved energy transfer in electrophosphorescent devices. [J]. Appl. Phys. Lett. 1999, 74, 442-444.
[27] Coppo P,Duati M,Kozhevnikov V N,Hofstraat J W,Cola L D.White-light emission from an assembly comprising luminescent iridium and europium complexes. [J]. Angew. Chem. 1nt. Ed., 2005, 44: l806-l8l0.
[28] Montes V A, Boliar C P, Agarwal N, Shinar J, Jr A P. Molecular-wire behavior of OLED materials: exciton dynamics in multichromophoric Alq3-oligofluorene-Pt(Ⅱ) porphyrin triads. [J]. J. Am. Chem. Soc., 2006, 128: 12436-12438.
[29] Montes V A, Bolivar C P, Estrada L A, Shinar J, Jr A P. Ultrafast dynamics of triplet excitons in Alq3-bridge-Pt(Ⅱ) porphyrin electroluminescent materials. [J]. J. Am. Chem. Soc. 2007, 129: 12598-12599.
[30] Yuji H, Kenji S, Kenichi. JP8315983, 1996.
[31] Williams E L, Haavisto K, Li J, Jabbour J E. Excimer-based white phosphorescent organic light emitting diodes with nearly 100% internal quantum efficiency. [J]. Adv. Mater. 2007, 19, 197-202.
[32] Adamovich V, Brooks J, Tamayo A, Alexander A M, Djurovich P I, D’Andrade B W, Adachi C, Forrest S R, Thompson M E. High efficiency single dopant white electrophosphorescent light emitting diodes. [J]. New J. Chem., 2002,26, 1171-1178.
[33] Wang Y F, Deng X P, Liu Y, Ni M J, Liu M, Tan T, Li X, Zhu W, Cao Y. White emission from dinuclear cyclometalated platinum(Ⅱ) complex in single-emitting layer PLEDs. [J]. Tetra. 2011, 67 ,2118-2124.
[34]Kido J, Hongawa K, Okuyama K, Nagai K. White light-emitting organic electroluminescent devices using the poly(N-vinylcarbazole) emitter layer doped with three fluorescent dyes. [J]. Appl. Phys. Lett. 64 (1994) 815-817.
[35] D’Andrade B W, Holmes R J, Forrest S R. Efficient organic electrophosphorescent white-light-emitting device with a triple doped emissive layer.[J]. Adv. Mater. 2004 , 16 ,624-628 .
[36] Wu H, Zou J, Liu F, Wang L, Mikhailovsky A, Bazan G C, Yang W, Cao Y. Efficient single active layer electrophosphorescent white polymer light-emitting diodes. [J]. Adv. Mater. 2008, 20, 696-702.
[37] D’Andrade B W, Brooks J, Adamovich V, Thompson M E, Forrest S R. White light emission using triplet excimers in electrophosphorescent organic light-emitting devices. [J]. Adv. Mater. 2002, 14, 1032-1036.
[38] Jiang J, Xu Y, Yang W, Guan R, Liu Z, Zhen H, Cao Y. High-efficiency white light single polymer by mixing singlet and triplet light- emitting. [J]. Adv. Mater. 2006, 18, 1769-1773.
[39] Zhang K, Chen Z, Yang C, Tao Y, Zou Y, Qin J, Cao Y. Stable white electroluminescence from single fluorene-based copolymers: using fluorenone as the green fluorophore and an iridium complex as the red phosphor on the main chain. [J]. J. Mater. Chem. 2008, 18, 291-298
[40] Reineke S, Lindner F, Schwartz G, Seidler N, Walzer K, Lüssem B, Leo K. White organic light-emitting diodes with fluorescent tube efficiency. [J]. Nature. 2009, 459, 234-238.
[41] Wang Q, Ding J Q, Ma D G, Cheng Y X, Wang L X, Wang F S. Manipulating charges and excitons within a single-host system to accomplish efficiency/CRI/color-stability trade-off for high-performance OWLEDs. [J]. Adv. Mater. 2009, 21, 2397-2401.
[42] Kanno H, Holmes R J, Sun Y, Kena-Cohen S, Forrest S R. White stacked electrophosphore- scent organic light-emitting devices employing MoO3 as a charge-generation layer. [J]. Adv. Mater. 2006, 18, 339-342.
[43] Cho T Y, Lin C L, Chang C H, Wu C C. [J]. Proceeding of SID’06, 1284, June 4-9, 2006, San Francisco USA.
[44] D’Andrade B W, Adamovich V, Hewitt R, Hack M, Brown J J. Phosphorescent organic light-emitting devices for solid-state lighting. [J]. Proceedings Proc. SPIE-Int. Soc. Opt. Eng. 2005 , 5937 , 1-7.
[45] Gather M C, K(o|¨)hnen A, Falcou A, Becker H , Meerholz K. Solution-processed full-color polymer organic light-emitting diode displays fabricated by direct photolithography. [J]. Adv. Funct. Mater. 2007 , 17 , 191-200. [46 ] D’Andrade B W, Brooks J, Thompson M E, Forrest S R. Controlling exciton diffusion in multilayer white phosphorescent organic light emitting devices.[J]. Adv. Mater. 2002, 14, 147-151.
[47] Smith G B, Dezeny G C, Hughes D L, King A O, Verheven T R. Mechanistic studies of the suzuki cross-coupling reaction. [J]. J. Org. Chem., 1994, 59, 8151-8156.
[48] Saito S, Tsutsui T, Ear M, et al. Design of organic electroluminescent materials and devices [J]. Mol. Cryst. Liq. Ctyst., 1994, 253, 125-132.
[49] Feng R, Jiang F L, Wu M Y, Chen L, Yan C F, Hong M C. Structures and photoluminescent properties of the lanthanide coordination complexes with hydroxyquinoline carboxylate ligands. [J]. Cryst. Growth. Des. 2010, 10, 2306-2313.
[50] Adachi C, Kwong R C, Djurovich P, Adamovich V, Baldo M A, Thompson M E, Forrest S R. Endothermic energy transfer: A mechanism for generating very efficient high-energy phosphorescent emission in organic materials. [J]. Appl. Phys. Lett., 2001, 79, 2082-2084.
[51] Clem T A, Kavulak F J, Westling E J, Frechet M J, Cyclometalated platinum polymers: synthesis, photophysical properties and photovoltaic performance. [J]. Chem. Mater., 2010, 22, 1977-1987.
[2] Slamansky S, Djovid P, Murphy D L, Abdd R F, Thompson M E. Synthesis andcharacterization of phosphorescent cyclometalated Iridium complexes. [J]. Inorg. Chem. 2001, 40,1704-1711.
[3] (a)Li C L, Su Y J, Tao Y T, Liu R S. Yellow and red electrophosphors based on linkage isomersof iridium phenylisoquinoline complexes: Distinct behaviors in photophysical and electroluminanceproperties. [J]. Adv. Funct. Mater. 2005, 15, 387-395. (b) Nam S C, Park J H, Lee S K,Lee J, Shim H K, Park M J, Hwang D H, Jung B J. Saturated and efficient red light-emittingfluorene-based alternating polymers containing phenothiazine derivatives. [J]. Macromolecules.2006, 39, 177-183.
[4] Duan J P, Sun P P, Cheng C H. New iridium complexes as highly efficient orange-red emittersin organic light-emitting diodes. [J]. Adv. Mater. 2003, 15, 224-228.
[5] Jiang C Y, Yang W, Peng J B, Xiao S, Cao Y. High-efficiency, saturated red-phosphorescentpolymer light-emitting diodes based on conjugated and non-conjugated polymers doped with an Ircomplex. [J]. Adv. Mater. 2004, 16, 537-541.
[6] Song Y H, Yeh S J, Chen C T, Lee G H. Bright and efficient, non-doped, phosphorescentorganic red-light-emitting diodes bright and efficient, non-doped, phosphorescent organicred-light-emitting diodes. [J]. Adv. Funct. Mater. 2004, 14, 1221-1226.
[7] Huang W S, Liu J T, Chein C H, Sun S S, Tao Y .,Wen Y S. Highly phosphorescentbis-cyclometalated iridium complexes containing benzoimidazole-based ligands. [J]. Chem. Mater.2004, 16, 2480-2488.
[8] Lu W, Chan M C W, Zhu N, Che C M, Li C, Hui Z. Structral and spectroscopic studies onPt Pt andπ-πinteractions in luminescent multinuclear cyclometalated platinum (Ⅱ) homologuestethered by oligophosphine auxiliaries. [J]. J. Am. Chem. Soc. 2004, 126, 7639-7651.
[9] Chan S C, ChanM C W, Wang Y, Che C W, Cheung K K, Zhu N. Organic Light-emittingmaterialsBased on bis (a rylacetylide ) platinum (Ⅱ) complexes bearing substituted bipyridine andphenanthroline ligands: photo-and electroluminescence from 3MLCT excited states. [J]. J. Chem.Eur. 2001, 7, 1480-1490.
[10] Huertas S, Hissler M, McGarrah J E, Lachicotte J E, Eisenberg R. Syntheses and structuralcharacterization of luminescent platinum (Ⅱ) complexes containing di-tert-butylbipyridine andnew 1, 1-dithiolate ligands. [J]. Inorg. Chem. 2001, 40, 1183-1188.
[11] Pomestchenko I E, Luman C R, Hissler M, Ziessel R, Castellano F N. Room temperaturephosphorescence from a platinum (Ⅱ) diimine bis( pyrenylacetylide ) complex. [J]. Inorg. Chem.2003, 42, 1394 -1396.
[12] Anbalagan V, Srivastava T S. Spectral and photophysical properties of mono and dinuclear Pt (Ⅱ) and Pd (Ⅱ) complexes: An unusual emission behavior. [J].Polyhedron. 2004, 23, 3173-3183.
[13] Kato M, Okamura T, Yamamoto H, Ueyama N. Effects of the intramolecular NH hydrogen bond in mono-nuclear platinum (Ⅱ) and palladium (Ⅱ) complexes with 2, 2’-bipyridine and benzenethiol derivatives. [J]. Inorg. Chem. 2005, 44, 1966-1972.
[14] Brooks J, Babayan Y, Lamansky S, Djurovich P I, Bau R, Thompson M E. Synthesis and characterization of phosphorescent cyclometalated platinum Complexes. [J]. Inorg. Chem. 2002, 41, 3055-3066.
[15] Kavitha J, Chang S Y, Chi Y, Yu J K, Hu Y H, Chou P H, Peng S M, Lee G H, Tao Y T, Chien C H, Carty A J. In search of high-performance platinum (Ⅱ) phosphorescent materials for the fabrication of red electro-phosphorescent devices. [J]. Adv. Funct. Mater. 2005, 15, 223-229.
[16] Lai S W, Chan M C W, Cheung T C, Peng S M, Che C M. Probing d8-d8 interactions in luminescent mono- and binuclear cyclometalated platinum (Ⅱ) complexes of 6-Phenyl-2, 2′-bipyridines. [J]. Inorg. Chem. 1999, 38, 4046-4055.
[17] Lu W, Mi B X, Chan M C W, Hui Z, Zhu N, Lee S T, Che C M. [(C^N^N)Pt(C≡C)nR] (HC^N^N=6-aryl-2, 2′-bipyridine, n=1～4, R=aryl, SiMe3) as a new class of light-emitting materials and their applications in electrophosphorescent devices. [J]. Chem. Commun. 2002, 206-207.
[18] Lu W, Mi B X, Chan M C W, Hui Z, Che C M, Zhu N, Lee S T. Light-emitting tridentate cyclometalated platinum (Ⅱ) complexes containingσ-alkynyl auxiliaries: Tuning of photo and electrophosphorescence. [J]. J. Am. Chem. Soc. 2004, 126, 4958-4971.
[19] Williams J A G, Beeby A, Davies E S, Weinstein J A, Wilson C. An alternative route to highly luminescent platinum (Ⅱ) complexes: cyclometalation with N^C^N coordinating dipyridylb- enzene ligands. [J]. Inorg. Chem. 2003, 42, 8609-8611.
[20] Farley S. J., Rochester D. L., Thompson A. L., Howard J. A. K., Williams J. A. G. Controlling emission energy, Self-quenching and excimer formation in highly luminescent N^C^N- coordinated platinum (Ⅱ) complexes. [J]. Inorg. Chem. 2005, 44, 9690-9703.
[21] Sotoyama W, Satoh T, Sawatari N, Inoue H. Efficient organic light-emitting diodes with phosphorescent platinum complexes containing N^C^N-coordinating tridentate ligand. [J]. Appl. Phys. Lett. 2005, 86, 153505.
[22] Baldo M A, O’Brien D F, You Y, Shoustikov A, Sibley S, Thompson M E, Forrest S R. Highly efficient phosphorescent emission from organic electroluminescent devices. [J]. Nature. 1998, 395, 151-154.
[23] Kwong R C, Sibley S, Dubovoy T, Baldo M, Forrest S R, Thompson M E. Efficient, saturated red organic light emitting devices based on phosphorescent platinum (Ⅱ) porphyrins. [J]. Chem. Mater. 1999, 11, 3709-3713.
[24] Xiang H F, Chan S C, Wu K K Y, Che C M, Laib P T. High-efficiency red electrophosphores- cence based on neutral bis(pyrrole)-diimine platinum (Ⅱ) complex. [J]. Chem. Commun. 2005, 1408-1410.
[25] Lin Y Y, Chan S C, Chan M C W, Hou Y J, Zhu N, Che C M, Liu Y, Wang Y. Structural, photophysical,and electrophosphorescent properties of platinum (Ⅱ) complexes supported by tetradentate N2O2 Chelates. [J]. Chem. Eur. J. 2003, 9, 1263-1272.
[26] O’Brien D F, Baldo M A, Thompson M E, Forrest S R. Improved energy transfer in electrophosphorescent devices. [J]. Appl. Phys. Lett. 1999, 74, 442-444.
[27] Coppo P,Duati M,Kozhevnikov V N,Hofstraat J W,Cola L D.White-light emission from an assembly comprising luminescent iridium and europium complexes. [J]. Angew. Chem. 1nt. Ed., 2005, 44: l806-l8l0.
[28] Montes V A, Boliar C P, Agarwal N, Shinar J, Jr A P. Molecular-wire behavior of OLED materials: exciton dynamics in multichromophoric Alq3-oligofluorene-Pt(Ⅱ) porphyrin triads. [J]. J. Am. Chem. Soc., 2006, 128: 12436-12438.
[29] Montes V A, Bolivar C P, Estrada L A, Shinar J, Jr A P. Ultrafast dynamics of triplet excitons in Alq3-bridge-Pt(Ⅱ) porphyrin electroluminescent materials. [J]. J. Am. Chem. Soc. 2007, 129: 12598-12599.
[30] Yuji H, Kenji S, Kenichi. JP8315983, 1996.
[31] Williams E L, Haavisto K, Li J, Jabbour J E. Excimer-based white phosphorescent organic light emitting diodes with nearly 100% internal quantum efficiency. [J]. Adv. Mater. 2007, 19, 197-202.
[32] Adamovich V, Brooks J, Tamayo A, Alexander A M, Djurovich P I, D’Andrade B W, Adachi C, Forrest S R, Thompson M E. High efficiency single dopant white electrophosphorescent light emitting diodes. [J]. New J. Chem., 2002,26, 1171-1178.
[33] Wang Y F, Deng X P, Liu Y, Ni M J, Liu M, Tan T, Li X, Zhu W, Cao Y. White emission from dinuclear cyclometalated platinum(Ⅱ) complex in single-emitting layer PLEDs. [J]. Tetra. 2011, 67 ,2118-2124.
[34]Kido J, Hongawa K, Okuyama K, Nagai K. White light-emitting organic electroluminescent devices using the poly(N-vinylcarbazole) emitter layer doped with three fluorescent dyes. [J]. Appl. Phys. Lett. 64 (1994) 815-817.
[35] D’Andrade B W, Holmes R J, Forrest S R. Efficient organic electrophosphorescent white-light-emitting device with a triple doped emissive layer.[J]. Adv. Mater. 2004 , 16 ,624-628 .
[36] Wu H, Zou J, Liu F, Wang L, Mikhailovsky A, Bazan G C, Yang W, Cao Y. Efficient single active layer electrophosphorescent white polymer light-emitting diodes. [J]. Adv. Mater. 2008, 20, 696-702.
[37] D’Andrade B W, Brooks J, Adamovich V, Thompson M E, Forrest S R. White light emission using triplet excimers in electrophosphorescent organic light-emitting devices. [J]. Adv. Mater. 2002, 14, 1032-1036.
[38] Jiang J, Xu Y, Yang W, Guan R, Liu Z, Zhen H, Cao Y. High-efficiency white light single polymer by mixing singlet and triplet light- emitting. [J]. Adv. Mater. 2006, 18, 1769-1773.
[39] Zhang K, Chen Z, Yang C, Tao Y, Zou Y, Qin J, Cao Y. Stable white electroluminescence from single fluorene-based copolymers: using fluorenone as the green fluorophore and an iridium complex as the red phosphor on the main chain. [J]. J. Mater. Chem. 2008, 18, 291-298
[40] Reineke S, Lindner F, Schwartz G, Seidler N, Walzer K, Lüssem B, Leo K. White organic light-emitting diodes with fluorescent tube efficiency. [J]. Nature. 2009, 459, 234-238.
[41] Wang Q, Ding J Q, Ma D G, Cheng Y X, Wang L X, Wang F S. Manipulating charges and excitons within a single-host system to accomplish efficiency/CRI/color-stability trade-off for high-performance OWLEDs. [J]. Adv. Mater. 2009, 21, 2397-2401.
[42] Kanno H, Holmes R J, Sun Y, Kena-Cohen S, Forrest S R. White stacked electrophosphore- scent organic light-emitting devices employing MoO3 as a charge-generation layer. [J]. Adv. Mater. 2006, 18, 339-342.
[43] Cho T Y, Lin C L, Chang C H, Wu C C. [J]. Proceeding of SID’06, 1284, June 4-9, 2006, San Francisco USA.
[44] D’Andrade B W, Adamovich V, Hewitt R, Hack M, Brown J J. Phosphorescent organic light-emitting devices for solid-state lighting. [J]. Proceedings Proc. SPIE-Int. Soc. Opt. Eng. 2005 , 5937 , 1-7.
[45] Gather M C, K(o|¨)hnen A, Falcou A, Becker H , Meerholz K. Solution-processed full-color polymer organic light-emitting diode displays fabricated by direct photolithography. [J]. Adv. Funct. Mater. 2007 , 17 , 191-200. [46 ] D’Andrade B W, Brooks J, Thompson M E, Forrest S R. Controlling exciton diffusion in multilayer white phosphorescent organic light emitting devices.[J]. Adv. Mater. 2002, 14, 147-151.
[47] Smith G B, Dezeny G C, Hughes D L, King A O, Verheven T R. Mechanistic studies of the suzuki cross-coupling reaction. [J]. J. Org. Chem., 1994, 59, 8151-8156.
[48] Saito S, Tsutsui T, Ear M, et al. Design of organic electroluminescent materials and devices [J]. Mol. Cryst. Liq. Ctyst., 1994, 253, 125-132.
[49] Feng R, Jiang F L, Wu M Y, Chen L, Yan C F, Hong M C. Structures and photoluminescent properties of the lanthanide coordination complexes with hydroxyquinoline carboxylate ligands. [J]. Cryst. Growth. Des. 2010, 10, 2306-2313.
[50] Adachi C, Kwong R C, Djurovich P, Adamovich V, Baldo M A, Thompson M E, Forrest S R. Endothermic energy transfer: A mechanism for generating very efficient high-energy phosphorescent emission in organic materials. [J]. Appl. Phys. Lett., 2001, 79, 2082-2084.
[51] Clem T A, Kavulak F J, Westling E J, Frechet M J, Cyclometalated platinum polymers: synthesis, photophysical properties and photovoltaic performance. [J]. Chem. Mater., 2010, 22, 1977-1987.