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混合发光层有机电致发光器件中的多重成分发射 总被引:3,自引:3,他引:0
以等摩尔空穴传输材料TPD和电子传输材料PBD组成结构为ITO/TPD/TPD∶PBD/PBD/Al的混合物发光层有机电致发光(EL)器件,观察到了相对于组成材料的荧光光谱红移的宽发射带。通过比较EL光谱,光致发光光谱及EL光谱分解,表明电致发光中同时包含单体发射、激基复合物和电荷对复合物的发射。激基复合物为TPD的激发态TPD*与PBD的基态相互作用形成TPD*PBD类型的复合物,电荷对复合物是带电荷的空穴传输分子(D+)的空穴和电子传输分子(A-)的电子交叉复合而形成的(D+-A-)*复合物。各激发态在电场作用下呈现不同的形成机理和复合过程,并且单体发射和激发态复合物的比例随电场而变化,导致发射光谱随电场增强而蓝移。该器件的最高亮度和最大外部量子效率分别为240 cd·(cm2)-1和0.49%。有机固态界面激基复合物或电荷对复合物的发射常出现宽的红移发射带,是调节发光颜色的有效手段。 相似文献
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具有分子间电荷转移激发态特性的激基复合物(Exciplex)体系,由于前线分子轨道的分离特性——最高占有轨道(Highest occupied molecular orbital,HOMO)集中分布于给体分子上,最低空轨道(Lowest unoccupied molecular orbital,LUMO)集中分布于受体分子上,因此具有极小的单线态-三线态能级差(ΔEst)以及热活化延迟荧光(Thermally activated delayed fluorescence,TADF)特性。因此,激基复合物体系的理论内量子效率可以达到100%。由于构建激基复合物体系的给体分子具有空穴传输特性,受体分子具有电子传输特性,因此,激基复合物体系具有平衡的载流子迁移特性,这使得激基复合物体系在作为发光层材料以及混合主体材料制备电致发光器件时具有平衡载流子迁移、扩大激子复合区域、提高器件效率以及降低效率滚降的优势。本文将讨论和总结基于激基复合物激发态体系的电致发光材料与器件基本原理、设计思路以及近期的研究进展。 相似文献
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从荧光-磷光复合结构的有机电致发光器件的研究入手,采用OXD-7作为蓝色荧光发光层,Ir(MDQ)2acac掺杂在母体材料作为红橙磷光发光层,设计制备了双波段白光有机电致发光器件。研究中发现,OXD-7,Alq3和NPB的三组分协同作用可以导致电致激基复合物的产生,以及由此导致的光谱红移,并使得器件发光效率降低。通过插入TDAF中间层可以有效地抑制激基复合物的产生,同时,通过控制载流子传输的平衡,以及磷光材料的掺杂浓度,可以获得器件发光亮度、效率的提升。 相似文献
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以TTA为配体合成了新的共掺杂稀土配合物Tb0.5Eu0.5(TTA)3Dipy,通过与PVK的掺杂,制备了以PVK:Tb0.5Eu0.5(TTA)3 Dipy为发光层的结构为:ITO/PVK:Tb0.5Eu0.5(TTA)3Dipy/BCP/Al的发光器件,在直流电压的驱动下,发现了铕在612 nm处的特征发射,和PVK在410 nm处的发光.此外,还观察到了位于490 nm处的新的发光峰,通过分析研究,认为新的发光来自于稀土配合物的配体和BCP之间相互作用形成的电致激基复合物.用PBD代替了BCP作为电子传输层,制备了结构为:ITO/PVK:Tb0.5Eu0.5(TTA)3DiPy/PBD/Al的发光器件,得到了纯的红色发光. 相似文献
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利用溶液旋涂的方法,通过改变复合功能层中poly(N-vinylcarbazole)(PVK)和N,N′-bis-(1-naph-thyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine(NPB)的质量比,制备结构为indium-tin-oxide(ITO)/PVK:NPB/2,9-dimenthyl-4,7-diphenyl-1,10-phenanthroline(BCP)/Mg:Ag的有机电致发光器件,并对器件的电致发光特性进行了表征。研究结果表明,当复合功能层中PVK和NPB的质量比为1:1时器件性能最好,在该器件的电致光谱中,除了NPB的本征谱峰外,在长波方向还出现了一个位于640nm处的谱峰,这是PVK和NPB产生的电致激基复合物发光,并且随着驱动电压的增加,电致激基复合物的发光强度也相对增强。 相似文献
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Exciplex formation and electroluminescent absorption in ultraviolet organic light-emitting diodes 下载免费PDF全文
We investigated the formation of exciplex and electroluminescent absorption in ultraviolet organic light-emitting diodes(UV OLEDs) using different heterojunction structures.It is found that an energy barrier of over 0.3 eV between the emissive layer(EML) and adjacent transport layer facilitates exciplex formation.The electron blocking layer effectively confines electrons in the EML,which contributes to pure UV emission and enhances efficiency.The change in EML thickness generates tunable UV emission from 376 nm to 406 nm.In addition,the UV emission excites low-energy organic function layers and produces photoluminescent emission.In UV OLED,avoiding the exciplex formation and averting light absorption can effectively improve the purity and efficiency.A maximum external quantum efficiency of 1.2%with a UV emission peak of 376 nm is realized. 相似文献
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Organic single-quantum-well electroluminescent device 总被引:1,自引:0,他引:1
Huang Jingsong Xie Zhiyuan Yang Kaixia Li Chuannan Liu Shiyong Wu Fang Tian Wenjing Shen Jiacong 《Optical and Quantum Electronics》2000,32(2):117-123
A new kind of single-quantum-well electroluminescent (EL) device consists of a hole transport N,N-Bis(3-methyphenyl)-N,N-diphenylbenzidine(TPD) layer, and electron transport 8-(quinolinolate)-aluminum(Alq) layer and a light emitting layer of Alq doped with 5,6,11,12-tetraphenylnaphthacene (rubrene) has been fabricated by the multisource-type high-vaccum organic molecular deposition. The dopant rubrene is as a potential well, and the undoped Alq layer is as a barrier layer. The EL spectra shows the spectral narrowing and the emission peak energy blue-shift, and the efficiency and luminance of the device have been significantly improved. The experimental phenomena is explained as the result of recombination of carriers from the quantized energy state. 相似文献
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White organic light-emitting diodes based on electroplex from polyvinyl carbazole and carbazole oligomers blends 下载免费PDF全文
White organic light-emitting diodes with a blue emitting
material fluorene-centred ethylene-liked carbazole oligomer (Cz6F)
doped into polyvinyl carbazole (PVK) as the single light-emitting
layer are reported. The optical properties of Cz6F, PVK, and PVK:Cz6F
blends are studied. Single and double layer devices are fabricated
by using PVK: Cz6F blends, and the device with the configuration of
indium tin oxide (ITO)/PVK:Cz6F/ tris(8-hydroxyquinolinate)aluminium
(Alq3)/LiF/Al exhibits white light emission with Commission
Internationale de l'éclairage chromaticity coordinates of (0.30,
0.33) and a brightness of 402~cd/m2. The investigation reveals
that the white light is composed of a blue--green emission
originating from the excimer of Cz6F molecules and a red emission
from an electroplex from the PVK:Cz6F blend films. 相似文献
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制备了三苯胺化合物4,4′,4″-三(咔唑-9-基)三苯胺(TCTA)的单层器件ITO/MoO3/TCTA/LiF/Al和TCTA/TPBi双层异质结器件ITO/NPB/TCTA/TPBi/Bphen/LiF/Al,研究了TCTA的双分子发光现象。通过测试器件的光电性能和薄膜的稳态光谱,得出以下结论:(1)单层器件的电致发光光谱有425 nm和600 nm两个发光峰。与TCTA薄膜的光致发光光谱对比,可知425 nm附近的蓝色发光峰来源于TCTA单体发光,而600 nm附近的橙色发光应为TCTA二聚体electromer的发光。蓝色和橙色发光混合,使单层器件发光颜色表现为白色,对应色坐标为(0.381,0.343)。(2)TCTA/TPBi双层异质结器件的电致发光光谱为440 nm的单峰,器件的最大发光亮度为930 cd/m2,发光性能明显优于单层器件。结合薄膜TCTA、TPBi和TCTA/TPBi的光致发光光谱和紫外-可见光吸收光谱,可知双层器件的发光来自TCTA+TPBi-电致激基复合物。双层器... 相似文献
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利用一种新型有机金属配合物二(2-(4-三氟甲基-2-羟基苯基)苯并噻唑锌(Zn(4-TfmBTZ)2),基于NPB/Zn(4-TfmBTZ)2界面电致激基复合物,制备了一系列异质结量子阱结构有机电致白光器件.结果表明,量子阱结构可以有效提高界面电致激基复合物的发光效率以及器件的显色指数和色度稳定性.得出器件ITO/NPB (60 nm)/Zn(4-TfmBTZ)2(3.0 nm)/NPB (4.0 nm)/Zn(4-TfmBTZ)关键词:
二(2-(4-三氟甲基-2-羟基苯基)苯并噻唑锌
电致激基复合物
量子阱
白光 相似文献
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J.S. Huang K.X. Yang Z.Y. Xie S.Y. Liu H.J. Jiang 《Optical and Quantum Electronics》2001,33(2):165-172
A white light-emitting organic electroluminescent (EL) device with multilayer thin-film structure, which shows high-brightness and high-efficiency, is demonstrated. The device structure of glass substrate/indium–tin oxide/poly(N-vinylcarbazole) (PVK)/1,1,4,4-tetraphenyl-1,3-butadiene/8-(quinolinolate)-aluminum (Alq) doped with 5,6,11,12-tetraphenylnaphthacene/Alq/Mg/Al was employed. The turn-on voltage is as low as 2.5 V. The white light emission covers a wide range of the visible region, and the Commission Internationale de 1' Eclairage coordinates of the emitted light are (0.319, 0.332) at 10 V. Bright white light, over 20 000 cd/m2, was successfully obtained at about 18 V, and the maximum efficiency reaches to 1.24 lm/W at 9 V. The reasons of obtaining high level EL properties of our device have been discussed. 相似文献
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《Solid State Communications》2002,121(2-3):145-147
A gadolinium ternary complex, tris(1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone) (phenanthroline) gadolinium [Gd(PMIP)3(Phen)] was synthesized and used as a light emitting material in the organic electroluminescent (EL) devices. The triple layer device with a structure of indium tin oxide (ITO)/N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD) (20 nm)/Gd(PMIP)3(Phen) (80 nm)/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (bathocuproine or BCP) (20 nm)/Mg: Ag(200 nm)/Ag(100 nm) exhibited green emission peaking at 535 nm. A maximum luminance of 230 cd/m2 at 17 V and a peak power efficiency of 0.02 lm/w at 9 V were obtained. 相似文献
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Organic device with structure of indium tin oxide (ITO)/1,3,5-tris-(3-methylphenylphenylamino)triphenylamine (m-MTDATA)/2-tert-butyl-9,10-di-beta-naphthylanthracene (TBADN)/2,9-dimethyl-4,7-diphenyl-1,10-phenan-throline (BCP)/LiF/Al, was fabricated, which show high efficient white electroluminescence (EL) or photovoltaic (PV) properties when it was driven by direct current (DC) bias or illuminated by ultraviolet (UV) light. Under a DC bias, the device shows efficient white EL emission. A maximum luminous efficiency of 1.1 lm/W was obtained at 8 V, which corresponds the Commission International de L’Eclairage coordinates (CIE) of (x = 0.298, y = 0.365). When the bias was increased to 12 V, the device shows bright white emission with the maximum brightness of 4300 cd/m2, corresponding CIE coordinates of (x = 0.262, y = 0.280). When the diode was irradiated by a 365 nm UV-light (4 mW/cm2), the open-circuit voltage (Voc) of 1.2 V, short-circuit (Isc) of 0.065 mA/cm2, fill factor (FF) of 0.24 and power conversion efficiency of 0.47% have been determined, respectively. The generation mechanisms of white light and PV of the bi-functional diode were discussed as well. 相似文献
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Huang Jingsong Xie Zhiyuan Yang Kaixia Li Chuannan Liu Shiyong Li Yanqin Wang Yue Shen Jiacong 《Optical and Quantum Electronics》1999,31(12):1227-1233
Remarkable improvement in efficiency and electroluminescence (EL) has been observed in an organic EL device, which consists of a hole-transport layer and a luminescent layer. The hole-transport layer is an N,N-bis(3-methyphenyl)-N,N-diphenylbenzidine film. The doped emitting layer consists of 8-(quinolinolate)-aluminum as the host and rubrene as the emission dopant. The doped cell with aluminum cathode demonstrated a luminance in excess of 20,000 cd/m2 and an external quantum efficiency of 2.7%, which is about four times and three times, respectively, greater than those of the undoped cell. The EL emission from the device shows spectral narrowing and a shift to higher energy. 相似文献