铱金属配合物磷光材料掺杂聚合物体系的电致发光特性

通过对一种新型贵金属铱的配合物磷光材料(pbi)₂Ir(acac)与咔唑共聚物进行物理掺杂, 制备了结构为indium-tin oxide(ITO)/poly(N-vinylcarbazole)(PVK): (pbi)₂Ir(acac)(x)/2,9-dimethyl-4,7-diphenyl-1,10-phenan throline(BCP)(20nm)/8-Hydroxyquinoline aluminum(Alq₃)(10nm)/Mg:Ag的聚合物电致磷光器件,研究了磷光聚合物掺杂体系在低掺杂浓度时(0.1%和0.5%(质量百分数,全文同))的光致发光(PL)和电致发光(EL)特性. 结果表明, 该掺杂体系的PL光谱和EL光谱中均同时存在主体材料PVK与磷光客体(pbi)₂Ir(acac)的发光光谱, 但主客体的发射强度不同,推测该掺杂体系在电致发光条件下, 同时存在主体材料到客体的不完全的能量传递和载流子直接俘获过程. 磷光掺杂浓度为0.1%的器件在19V电压下实现了白光发射, 色坐标为(0.32, 0.38), 掺杂浓度为0.5%的器件在20.6V电压下的最大发光亮度为11827 cd·m^-2, 而在13.4V电压下的最大流明效率为4.13 cd·A^-1. 关键词： 有机电致发光器件 铱配合物磷光 聚合物掺杂     

High performance polymer light-emitting diodes doped with a novel phosphorescent iridium complex

High performance polymer light-emitting diodes (PLEDs) based on a phosphor of noble metal complex bis(1,2-dipheny1-1H-benzoimidazole) iridium (acetylacetonate) [(pbi)₂Ir(acac)] doped in poly(N-vinylcarbazole) (PVK) host with various concentration were demonstrated. The photoluminescence (PL) and electroluminescence (EL) spectra of the PLEDs exhibited an emission intensity decrease of PVK and a gradually enhanced feature of (pbi)₂Ir(acac) with increased doping concentration. The device with a 5 wt% (pbi)₂Ir(acac) doped PVK system showed a high power efficiency of 3.84 lm/W and a luminance of 26,006 cd/m². The results indicated that both energy transfer and charge trapping have a significant influence on the performance of PLEDs. The devices have a broadened EL spectrum of full-width at half-maximum (FWHM) more than 100 nm, which can be realized for WOLEDs.     

Efficient white polymer light-emitting diodes based on a phosphorescent iridium complex and a fluorescent silole and carbazole copolymer

White polymer light-emitting diodes (WPLEDs) were fabricated with blue phosphorescent iridium bis(2-(4,6-difluorophenyl)-pyridinato-N,C²′) picolinate (FIrpic) and red fluorescent silole and carbazole copolymer PCz-MPTST within a poly(N-vinylcarbazole) (PVK): 1,3-bis[(4-tert-butylphenyl)-1,3,4- oxadiazolyl] phenylene (OXD-7) host matrix. Efficient white emission consisting two emission peaks was achieved with luminous efficiency of 9.2 cd/A and CIE coordinates of (0.37, 0.40). By means of transient photoluminescence response, energy transfer among the blending components was investigated and discussed.     

Iridium(III) Complexes with Orthometalated Phenylimidazole Ligands Subtle Turning of Emission to the Saturated Green Colour

A series of novel six iridium complexes (1–6) bearing two substituted phenylimidazole and an additional acetylacetone as the third co-auxilary ligand are reported. The lowest absorption band for all iridium complexes consist of a mixture of heavy atom Ir(III) enhanced ³MLCT and ³ π-π* transitions and the phosphorescent peak wavelength can be fine-tuned to cover the spectral range 455–518 nm with high quantum efficiencies. The peak wavelength of the dopants can be finely tuned depending upon the electronic properties of the substituents. On the basis of onset potentials of the oxidation and reduction, the HOMO-LUMO energies were calculated and the reported iridium complexes emit green light with exceeding higher efficiency.     

Enhancement of electroluminescent properties of organic optoelectronic integrated device by doping phosphorescent dye

Organic optoelectronic integrated devices(OIDs) with ultraviolet(UV) photodetectivity and different color emitting were constructed by using a thermally activated delayed fluorescence(TADF) material 4, 5-bis(carbazol-9-yl)-1, 2-dicyanobenzene(2 CzPN) as host. The OIDs doping with typical red phosphorescent dye [tris(1-phenylisoquinoline)iridium(Ⅲ), Ir(piq)_3], orange phosphorescent dye {bis[2-(4-tertbutylphenyl)benzothiazolato-N,C~(2')]iridium(acetylacetonate),(tbt)_2 Ir(acac)}, and blue phosphorescent dye [bis(2, 4-di-fluorophenylpyridinato)-tetrakis(1-pyrazolyl)borate iridium(Ⅲ), FIr6] were investigated and compared. The(tbt)_2 Ir(acac)-doped orange device showed better performance than those of red and blue devices, which was ascribed to more effective energy transfer. Meanwhile, at a low dopant concentration of 3 wt.%, the(tbt)_2 Ir(acac)-doped OIDs showed the maximum luminance, current efficiency, power efficiency of 70786 cd/m~2, 39.55 cd/A, and 23.92 lm/W, respectively, and a decent detectivity of 1.07 × 10~(11) Jones at a bias of -2 V under the UV-350 nm illumination. This work may arouse widespread interest in constructing high efficiency and luminance OIDs based on doping phosphorescent dye.     

非掺杂型高效绿色磷光有机电致发光器件

在空穴传输层TCTA与电子传输层TPBi之间引入磷光染料Ir(ppy)3超薄发光层,制备了结构为ITO/MoO_3(2 nm)/NPB(40 nm)/TCTA(10 nm)/Ir(ppy)3(xnm)/TPBi(40 nm)/LiF(1 nm)/Al(80 nm)的非掺杂磷光有机电致发光器件。通过调控非掺杂发光层的厚度,详细研究了Ir(ppy)3层厚度对器件性能的影响。实验结果表明,当非掺杂发光层厚度为0.2 nm时,器件的性能最好,器件的亮度、效率和外量子效率分别达到26 350 cd·m~(-2)、42.9 cd·A~(-1)和12.9%。研究结果表明,采用超薄的非掺杂发光层可以简化器件结构和制备工艺,获得高效率的OLED器件。     

一种基于环金属铱配合物的高效绿色聚合物电致发光器件

以2-苯基吡啶为主配体,3-乙酰基樟脑为辅助配体合成了一种新型的具有大空间位阻的环金属铱配合物Ir[(PPy)2(acam)],对它的化学结构和光物理性质进行了表征.以环金属铱配合物Ir[(PPy)2(acac)]的发光效率(0.34)为参照物,配合物在2-甲基四氢呋喃溶液中的光致发光效率为0.54,表明在配合物中引入...     

掺杂离子型配合物的高效聚合物白光发光二极管

研究了掺杂离子型铱配合物的单发光层聚合物白光器件.根据二元互补色获得白光的原理,所采用离子型橙光材料为六氟磷酸合[二(2-(萘基-1-基)吡啶)(1-乙基-2-(9-(2-乙基己基)-9H-咔唑-3-基)-1H-咪唑并[4,5-f][1,10]菲啰啉)铱(Ⅲ)]([(npy)₂Ir(c-phen)]PF₆),天蓝光材料为二(2-(4,6-二氟苯基)吡啶-N,C(2))吡啶甲酰合铱(Firpic).器件结构为氧化铟锡/苯磺酸掺杂聚乙烯基二氧噻吩(40 nm)/发光 关键词： 聚合物发光二极管 白光 二元互补色 离子型铱配合物     

Enhanced Device Performances of Blue‐Emitting PLEDs Coupled with Silver‐Nanoicosahedrons

Silver‐nanoicosahedron particles (AgNIPs) are produced by chemical reduction and photochemical methods and doped into the hole transport layer (HTL) or emissive layer (EML) of blue‐emitting polymer light‐emitting diodes (PLEDs) to improve their luminous efficiency. The optimal distributed‐densities of the AgNIPs are determined from current density–voltage–luminance measurements at different doping concentrations. The AgNIP dopant doses that maximize the average luminous efficiency of the proposed PLED are 6.71 µg cm^?2 in EML (achieving 3.48 cd A^?1) and 6.88 µg cm^?2 in HTL (achieving 3.35 cd A^?1). Although the luminous efficiencies of the blue‐emitting PLEDs fabricated by both doping methods are not significantly different, the maximum plasmonic enhancement (around 30‐fold) of the blue‐emitting PLED with AgNIPs in EML is red‐shifted to the green region (≈530 nm in the electroluminescence spectrum), seriously degrading the luminescent monochromaticity of the blue‐emitting PLED. The maximum plasmonic enhancement (around 33‐fold) of blue‐emitting PLED with AgNIPs in HTL occurred at 430 nm, overlapping the localized surface‐plasmon resonance extinctions of the AgNIPs in HTL (425 nm), thus favoring the enhancement of fluorescence emission. Therefore, to enhance the large‐area emission of blue‐emitting PLEDs, the AgNIPs should be doped in the HTL rather than the EML.     

Influence of Dopant Concentration on Electroluminescent Performance of Organic White-Light-Emitting Device with Double-Emissive-Layered Structure

A novel phosphorescent organic white-light-emitting device （WOLED） with contiguration of ITO/NPB/CBP： TBPe：rubrene/Zn（BTZ）2：Ir（piq）2（acac）/Zn（BTZ）2/Mg：Ag is fabricated successfully, where the phosphorescent dye bis （1-（phenyl）isoquinoline） iridium （Ⅲ） acetylanetonate （Ir（piq）2 （acac）） doped into bis-（2-（2-hydroxyphenyl） benzothiazole）zinc （Zn（BTZ）2） （greenish-blue emitting material with electron transport character） as the red emitting layer, and fluorescent dye 2,5,8,11-tetra-tertbutylperylene （TBPe） and 5,6,11,12-tetraphenyl-naphthacene （rubrene） together doped into 4,4＇-N,N＇-dicarbazole-biphenyl （CBP） （ambipolar conductivity material） as the blue-orange emitting layer, respectively. The two emitting layers are sandwiched between the hole-transport layer N ,N＇-biphenyl-N , N＇-bis （1-naph thyl）-（1,1＇-biphenyl）-4, 4 Cdiamine （NP B） and electron-transport layer （Zn（BTZ）2 ） The optimum device turns on at the driving voltage of 4.5 V. A maximum external quantum efficiency of 1.53%. and brightness 15000 cd/m^2 are presented. The best point of the Commission Internationale de 1＇Eclairage （CIE） coordinates locates at （0.335, 0.338） at about 13 V. Moreover, we also discuss how to achieve the bright pure white light through optimizing the doping concentration of each dye from the viewpoint of energy transfer process.     

Efficient green-phosphorescent light-emitting diodes based on polymeric binary-host systems

The fabrication of the green polymer light-emitting diodes based on emission from the phosphorescent molecule fac tris(2-phenylpyridine) iridium doped into a polymeric binary-host is reported. The main host used in the PLEDs was a non-conjugated polymer, poly(9-vinyl carbazole) (PVK). To realize the balanced transport of the holes and the electrons, a conjugated polymer, poly(9,9-dioctylfluorene) (PFO) was used as the assisting host. According to the experimental results, we found that the PLEDs can achieve the balance in charge transport and the recombination zone is still confined in the emissive layer by controlling the ratio of PVK to PFO. The luminous efficiency is enhanced by >40% while the external quantum efficiency can be increased by >38% in a polymeric binary-host system as compared to those of traditional device configuration, which is attributed to the balanced transport of the charged carrier.     

基于咪唑并吡啶类配体新型磷光材料的合成与表征

设计开发了系列新型咪唑并吡啶类铱(Ⅲ)配合物(BIPy)₂Ir(acac)、(PIPy)₂Ir(acac)、 (4'-MPIPy)₂-Ir(acac)。在化合物Ⅲ中,当R=Ph时得到(BIPy)₂Ir(acac)材料,其中BIPy和acac分别表示2-(4-联苯基)咪唑并吡啶和乙酰丙酮。将(BIPy)₂Ir(acac)掺杂在N,N'-二咔唑-(1,1'-联苯)-4,4'-二胺(CBP)中制备了高效OLEDs器件,器件的最大电流效率为26.7 cd/A,最大亮度为18 000 cd/cm²,色坐标为(0.32,0.60),是首次报道的新型苯基咪唑并吡啶类铱(Ⅲ)配合物绿色磷光材料。     

一种多层白色磷光有机电致发光器件的制备及性能研究

制备了一种结构为ITO/NPB/NPB:Ir(piq)₂(acac)/CBP:TBPe/BAlq:rubrene/BAlq/Alq₃/Mg:Ag的白色磷光有机电致发光器件.其中空穴传输型主体NPB掺杂磷光染料Ir(piq)₂(acac)作为红色发光层,双载流子传输型主体4,4′-N,N′-dicarbazole-biphenyl (CBP)掺杂TBPe作为蓝色发光层,电子传输型主体材料BAlq掺杂rubrene作为绿色发光层.以上发光层夹于 关键词： 电致发光 磷光染料 异质结 白光     

High-Efficiency White Light Emission Using a Phosphorescent Sensitizer in Organic Light-Emitting Devices

We have fabricated white organic light-emitting devices by using the phosphorescent material fac tris (2-phenylpyridine) iridium [Ir(ppy₃)] as a sensitizer, as a result, the efficiency of these devices is improved dramatically. Ir(ppy)₃ and the fluorescent dye 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7- tetramethyljulolidyl-9-enyl)(DCJTB) are co-doped into 4,4-N,N-dicarbazole-biphenyl (CBP) host, whose thickness affects both color and efficiency of the devices. Tris (8-hydroxyquinoline) aluminum (Alq) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine or BCP) are used as electron-transporting and exciton-blocking layers, respectively, and N,N-diphenyl-N,N-bis(1-naphthyl)-(1,1-biphenyl)-4,4-diamine (NPB) as a blue light-emitting as well as hole-transporting layer. The maximum efficiencies of the devices with 15 and 20 nm co-doped BCP tuning layer are 7.5 and 8.6 cd/A, respectively, and the former presents fairly pure white emission with CIE coordinates of (0.33, 0.32) at 10 V, which is very stable at various biases (10–19 V).     

Electroluminescence of organic light-emitting diodes consisting of an undoped (pbi)2Ir(acac) phosphorescent layer

The electroluminescence (EL) characteristics of phosphorescent organic light-emitting diodes (OLEDs) with an undoped bis(1,2-dipheny1-1H-benzoimidazole) iridium (acetylacetonate) [(pbi)₂Ir(acac)] emissive layer (EML) of various film thicknesses were studied. The results showed that the intensity of green light emission decreased rapidly with the increasing thickness of (pbi)₂Ir(acac), which was relevant to the triplet excimer emission. It suggested that the concentration quenching of monomer emission in the undoped (pbi)₂Ir(acac) film was mainly due to the formation of triplet excimer and partly due to the triplet-triplet annihilation (TTA) and triplet-polaron annihilation (TPA). A green OLED with a maximum luminance of 26,531 cd/m², a current efficiency of 36.2 cd/A, and a power efficiency of 32.4 lm/W was obtained, when the triplet excimer emission was eliminated. Moreover, the white OLED with low efficiency roll-off was realized due to the broadened recombination zone and reduced quenching effects in the EML when no electron blocking layer was employed.     

Efficient blue-green and white organic light-emitting diodes with a small-molecule host and cationic iridium complexes as dopants

Using cationic iridium complexes as dopants and a small molecule, 9,9-bis[4-(3,6-di-tert-butylcarbazol-9-yl)phenyl]fluorene, as the host, efficient organic light-emitting diodes (OLEDs) have been fabricated from a solution process. The blue-green OLEDs achieve a peak current efficiency of 19.8 cd?A^?1 and a maximum brightness of 17700 cd?m^?2. White OLEDs have been fabricated with a peak current efficiency of 16.8 cd?A^?1 and Commission Internationale de l’Éclairage coordinates around (0.37, 0.44). It is suggested that cationic iridium complexes, in addition to their use in light-emitting electrochemical cells, are promising phosphorescent dopants for solution-processed small-molecule OLEDs.     

基于Ir(ppy)3载流子直接复合发光的OLED机理研究

针对载流子在面式-三（2-苯基吡啶基-N,C^2’）铱（Ⅲ）（Ir（ppy）₃）上的聚集会对器件性能产生不良影响,在发光层中分别掺入4% 的双（2-（4,6-二氟苯基）吡啶基-N,C^2’）铱（Ⅲ）（吡啶-2-羧基）配合物（FIrpic）和4% 的4,4’,4"-三（咔唑-9-基）三苯胺（TCTA）,器件的性能有明显的提高,最高电流效率分别达到51 cd/A和43.1 cd/A,提高约79%和50%,我们将器件效率的提高归因于TCTA和FIrpic可以使聚集在Ir（ppy）₃界面的空穴向主体材料4,4’-二（咔唑-9-基）联苯（CBP）转移,进而可减弱对激子的猝灭作用。     

荧光染料和磷光染料激子形成截面的比较

为了比较单线态激子与三线态激子形成截面的大小,作者将荧光染料4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) 和磷光材料factris-(2-phenylpyridine) iridium [Ir(ppy)₃]共掺杂在N-vinylcarbazole (PVK)中作为发光层,制作了多层有机电致发光器件。通过对其光致发光及电致发光特性的研究,计算出Ir(ppy)₃激子的形成截面比DCJTB激子的形成截面大得多。     

Microwave Assisted Synthesis of a New Triplet Iridium(III) Pyrazine Complex

采用微波辅助加热方法,2,3-二苯基吡嗪(DPP)与水合三氯化铱(IrCl₃·3H₂O)反应制备了[Ir(DPP)₃],通过¹H NMR、元素分析和质谱方法对配合物结构进行了表征,并研究了配合物的吸收光谱和光致发光光谱. 结果表明,配合物Ir(DPP)₃在382和504 nm处存在单重态¹MLCT(金属到配体的电荷跃迁)和三重态³MLCT的吸收;在573 nm 处有较强的金属配合物三重态的磷光发射.     

Optimization of polymeric host composition for polymer-based electrophosphorescent devices

We have demonstrated an optimized polymeric host material comprising a blend of poly(9-vinylcarbazole) (PVK) and a fluorescent polymer for a highly efficient electrophosphorescence system. Although the chemical compatibility between the blue-emitting-fluorescent polymer and iridium complex, tris[2-phenylpyridine]iridium(III) (Ir-(ppy)₃), is very poor, efficient energy transfers from the blended host to the Ir complex was observed when a small amount of blue-emitting-fluorescent polymer was added to the PVK matrix. The device showed a maximum external quantum efficiency at 5 wt% blue-emitting-fluorescent polymer and 8 wt% Ir complex doping concentrations.