基于一种新型有机金属配合物的量子阱结构有机电致白光器件的性能研究

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}     

新型有机电致磷光白光器件的研究

制备了结构为ITO/NPB/TCTA/FIrpic∶TCTA/Ir(MDQ)2(acac)∶TmPyPB/FIrpic∶TmPyPB/TmPyPB/LiF/Al的有机电致磷光发光器件。通过在双蓝光发光层之间插入较薄的红光层Ir(MDQ)2(acac)∶TmPyPB调节载流子、激子在各发光层中的分布,并结合TCTA和TmPyPB对发光层内载流子和激子的有效阻挡作用,混合实现白光发射。研究了红光层在不同厚度、不同掺杂浓度下对器件发光性能的影响。结果表明,红光发光层厚度为2nm、质量浓度为5%时,结合蓝光发光层和红光发光层,实现了色坐标为(0.333,0.333)、最大发光效率为11.50cd/A的白光发射。     

白色有机电致发光器件中多组份电致激基复合物形成及抑制

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。     

利用级联式能量传递的有机电致发光器件

为了提高掺杂型有机电致发光器件(OLED)中主体发光材料与客体荧光染料间能量传递的效率,2-对联苯-8-羟基喹啉锌(Zn ₂)作为NPB : DCJTB掺杂体系的能量助传递剂,制备了结构如:ITO/NPB/NPB : DCJTB/Zn ₂/BCP/Al的有机电致发光器件。助传递剂Zn ₂的加入,能够两次利用Frster能量转移,实现NPB向DCJTB级联式的能量传递过程,提高低浓度时掺杂染料DCJTB红光发射的纯度;此外,还探讨了三者间能量传递的有效距离,即当助传递剂与掺杂体系的距离在小于10 nm的范围内,其参与能量传递的效率随着距离的增加而逐渐下降。     

TBVB用作蓝光发光层的非掺杂有机电致蓝光和白光器件

利用一种来源于PPV的发蓝光的齐聚物材料2,5,2',5'-tetra(4'-biphenylenevinyl)-biphenyl(TBVB)制作非掺杂的有机电致蓝光和白光器件。蓝光器件的结构为ITO/NPB/TBVB/Alq₃/LiF/Al,其中TBVB用作发光层;白光器件的结构为ITO/NPB/TBVB/rubrene/Alq₃/LiF/Al,其中TBVB与超薄层(平均“厚度”0.05~0.20nm)的Rubrene相结合用作发光层,二者分别发蓝光和黄光。在蓝光器件中,当TBVB的厚度为30nm时,器件发出色坐标为(0.20,0.26)的蓝光,其最大亮度和效率分别达到2154cd/m²和1.62cd/A。在白光器件中,可通过调节TBVB和Rubrene的厚度实现对器件发光色度的调节。当TBVB和Rubrene的厚度分别为10,0.15nm时,器件在亮度为4000cd/m²时发光色坐标为(0.33,0.34),非常接近白光等能点,且随着电压的变化始终处于白光区。当电压为16V时该器件达到最高亮度4025cd/m²;当电压为6V时器件有最高的效率3.2cd/A。     

利用激基复合物发光的有机白光电致发光器件

以NPB为空穴传输材料,(dppy)BF为发光层,Alq为电子传输层和色度调节层,制备了有机白光电致发光器件.该器件的白光发射是来自于(dppy)BF与NPB的固界表面形成的激基复合物发光,以及NPB与(dppy)BF发射的蓝光.该白光器件的色度稳定,在电压10～25V的变化范围内,色坐标变化由(0.29,0.33)到(0.31,0.35).器件在4V开启,12V电压下亮度和效率分别为200cd/m²和0.45lm/W.     

白色有机电致发光器件的制备及掺杂对其色度的影响

采用补色原理,制备黄、蓝双色发光层,且只对黄发光层进行掺杂浓度的调节,得到了较理想的白光器件,改善了工艺制程.所制器件结构为ITO/CuPc/NPB/NPB:DCJTB/NPB/BCP/AlQ/LiF/Al,NPB:DCJTB是黄色发光层.实验发现,器件的色度随着掺杂浓度的变化而变化,当DCJTB掺杂浓度为1.06%时,色度具有最佳值,其色坐标为(0.314 9,0.342 8),亮度为19 000 cd/m2,且当电压变化时,器件的色度仍然恒定在白光区.     

蓝色发光材料DPVBi掺杂DCJTB发光性质的研究

对蓝光材料DPVBi掺杂红光染料DCJTB的发光性质进行了研究。首先研究了DPVBi掺杂不同质量浓度DCJTB的光致发光，当掺杂质量浓度为0.1％时，光致发光得到白光(色度x=0．36，y=0．34)。基于光致发光的实验结果，以DPVBi掺杂不同质量浓度DCJTB作发光层，制备了结构为ITO／CuPc／NPB／DPVBi：DCJTB/Alq3／LiF／Al的器件，当掺杂质量浓度为0．08％时器件实现了白色发光(色度为x=0．25，y=0．32)。研究了该白光器件的电致发光性质，白光器件在14V时达到最高亮度7822cd／m^2。在20mA／cm^2电流密度驱动下的亮度为489cd/m^2，最大流明效率为1．75lm／W。     

新型蓝色荧光材料5,5',6,6'-四苯基-2,2'-联吡嗪的制备和发光性质

以乙二胺和二苯乙二酮为原料合成了5,6-二苯基-2,3-二氢吡嗪(Dpdhpz),Dpdhpz在Ir Cl3·3H2O或三氟化硼乙醚等路易斯酸作用下发生自身氧化偶联得到了5,5',6,6'-四苯基-2,2'-联吡嗪(Dbppz)。在四氢呋喃(THF)溶液中,Dbppz的光致发光(PL)为深蓝色,最大发射峰位于400 nm,CIE坐标为(0.16,0.03)。Dbppz在THF溶液中最大量子效率为89%,在聚苯乙烯薄膜(Dbppz质量分数5%)中的量子效率为78%。将Dbppz制备成器件结构为ITO/HAT-CN(5 nm)/NPB(40 nm)/Dbppz(20 nm)/Tm Py PB(40 nm)/Li F(1 nm)/Al(100 nm)的非掺杂电致发光器件。实验发现,该非掺杂器件并没有产生预期的蓝色发光,而是意外地得到了一个白光器件。我们推测产生白光发射的原因与发光层和空穴传输层之间相互作用有关。由于空穴传输层NPB的芳胺结构具有电子给体性质,而Dbppz的吡嗪结构具有电子受体结构,发光层与空穴传输层的界面发生了电子给体和电子受体的相互作用,形成了激基复合物。在电致发光(EL)光谱中,除了Dbppz发光材料在415 nm的发射外,在550 nm还出现强的激基复合物的发射。激基复合物的产生使得EL发射出现了长波长光谱,同时减弱了发光层的"本征"发光。蓝色"本征"发光与激基复合物的黄色发光构成了一个CIE坐标值为(0.27,0.33)(亮度100 cd/m2)的白光器件。器件最大外量子效率、最大功率效率和最大电流效率分别为44%、0.74 lm/W和1.04 cd/A。     

一种新型有机电致微腔结构的双模发射

采用结构Glass／DBR／ITO／NPB／NPB：Alq／Alq／Al制作了有机微腔电致发光器件。将空穴传输材料与发光材料以一定比例混合作为发光层，为了便于对比，在不改变有机层的膜厚的情况下同时制作了传统的异质结微腔器件，发现两种器件的发光光谱有很大不同，器件的复合效率与传统的异质结器件相比也得到了很大提高，这是因为将两种有机材料混合能消除界面势垒，提高器件的复合效率，从而提高了器件的发光性能，实现了微腔双模发射，且两个模式的半峰全宽分别为8nm和12nm。通过进一步优化器件结构可以实现微腔白光发射。     

The characterization of electroplex generated from the interface between 2-(4-trifluoromethyl-2-hydroxyphenyl)benzothiazole] zinc and N,N′-diphenyl-N,N′- bis(1-naphthyl)-(1,1′-biphenyl)-4,4′-diamine

The electroplex between (2-(4-trifluoromethyl-2-hydroxyphenyl)benzothiazole) zinc [Zn(4-TfmBTZ)₂] as an electron-acceptor and N,N′-diphenyl-N,N′-bis(1-naphthyl)-(1,1′-biphenyl)-4,4′-diamine (NPB) as an electron-donor was characterized by bilayer, blend, and multilayer quantum-well (MQW) device, respectively. The blend composition and quantum-well number are effective parameters for tuning electroluminescence color. White light with high color purity and color rendering index (CRI) was observed from these devices based on Zn(4-TfmBTZ)₂/NPB. Moreover, the blend and MQW devices all exhibit high operation stability, hence excellent color stability. For the device with 5 mol% NPB in blend layer, its Commission International Del’Eclairage (CIE) coordinate region is x=0.28–0.31, y=0.33–0.35 and CRI is 83.3–91.2 at 5–9 V. For MQW structure device with NPB of 60 nm thickness, its CIE coordinate region is x=0.29–0.32, y=0.31–0.34 and CRI=87.9–92.5 at 10–15 V. Such high color stability and purity and CRI, being close to ideal white light, are of current important for white OLED.     

Non-doped red to yellow organic light-emitting diodes with an ultrathin 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) layer

In this letter, bright non-doped red to yellow organic light-emitting diodes (OLEDs) with ultrathin 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) layer as the emitting layer were fabricated. It was investigated that the effect of the ultrathin DCJTB layer on the electroluminescent (EL) performance of OLEDs. The DCJTB layer was incorporated at different positions in the conventional tris(8-quinolinolato)-aluminum (AlQ)-based devices (ITO/NPB/AlQ/LiF/Al). The emission of DCJTB was dominative in the EL spectra of the devices, in which the position of 0.3 nm DCJTB layer was less than 10 nm from the NPB/AlQ interface. The EL peak emission of DCJTB shifted to blue side as DCJTB position moved gradually from AlQ to NPB layer. The highest brightness of the device with 0.3 nm DCJTB layer inserted into NPB reached 16,200 cd/m² at 15 V, with the CIE coordinates of (0.522, 0.439).     

荧光染料掺杂的高效率、高亮度白色有机电致发光器件

制备了结构为 ITO/NPB（30 nm）/Rubrene（0.2 nm）/CBP：Bczvbi（8 nm,x%）/Bphen（30 nm）/Cs₂CO₃：Ag₂O（2 nm,20%）/Al（100 nm）的器件。研究了Bczvbi掺杂浓度（x=5,10,15）对白光器件性能的影响。综合利用发光层中主客体之间的能量转移和空穴阻挡层的空穴阻挡特性,得到了高效率、高亮度的白色有机电致发光器件。当Bczvbi的掺杂质量分数为10%时,器件的效率和亮度都为最大。驱动电压为7 V时,最大电流效率为4.61 cd/A;驱动电压为9 V时,最大亮度为21 240 cd/m²。当驱动电压从4 V增加到9 V时,色坐标从（0.36,0.38）变化为（0.27,0.29）,均处于白光区域。     

发光层和空穴传输层对白色电致发光器件性能的影响

利用电子传输性能良好的苯并噻唑螯合锌(Zn(BTZ)₂)作为蓝光层，通过设计不同类型的空穴传输层并试验不同厚度的发光层后，制作了一种最佳厚度的双发光层白色电致发光器件：氧化铟锡(ITO)/N-N′-双(3-甲基苯基)-N-N′-二苯基-1-1′-二苯基-4-4′-二胺(TPD)∶N,N′-二(1-萘基)-N,N′-二苯基-1,1′-联苯-4-4′-二胺(NPB)(1∶0.0 关键词： 厚度 空穴传输层 白光 载流子     

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.     

High-efficiency Simple Structure White Organic Light-emitting Devices Based on Rubrene Ultrathin Layer

White organic light-emitting devices (WOLEDs) were fabricated with an ultrathin layer of rubrene inserted between NPB and TPBI. With a simple three-layer structure of ITO/NPB(50 nm)/rubrene(0.1 nm)/TPBI(50 nm)/LiF/Al, a white light with CIE coordinates of (0.31, 0.30) were generated. The device gave a maximum luminance efficiency of 2.04 lm/W at 5 V. Furthermore, with a multilayer structure of ITO/m-MTDATA(30 nm)/NPB(20 nm)/rubrene(0.1 nm)/TPBI(40 nm)/Alq₃(10 nm)/LiF/Al, the device reached a maximum luminance efficiency of 4.29 lm/W at 4 V and the luminance could exceed 10 000 cd/m² at 10 V.     

采用复合空穴注入层提高有机电致发光器件的性能

制备了以Ag/SAM/m-MTDATA为复合空穴注入层的NPB/Alq₃双层异质结发光器件,研究了器件的性能并与传统的器件进行了对比。考察了银膜厚度的变化对器件性能的影响。研究了光谱窄化以及微腔效应对器件的影响。研究结果表明:在ITO表面制备4-FTP自组装单分子膜修饰的5 nm厚的金属银膜,可以在保持阳极透明性的基础上,增强空穴的注入,改善界面的形貌,进而提高器件性能。制备的ITO/Ag/SAM/m-MTDATA/NPB/Alq₃/LiF/Al器件的启亮电压为4 V,最 大电流效率为6.9 cd/A, 最大亮度为34 680 cd/m²(12 V);优于以ITO为阳极的对比器件(25 300 cd/m² @12 V)。     

Improved performances of the organic light-emitting devices by doping in the mixed layer

The brightness, efficiency and lifetime of organic light-emitting diodes (OLEDs) were remarkably improved by doping in a mixed layer. In this device, the emitting layer consists of a mixture of -naphthylphenybiphenyl amine (NPB), tris (8-hydroxyquinolinolate) aluminum (Alq₃) (referred to as the mixed layer) and an emissive dopant 5,6,11,12-petraphenylnaphthacene (rubrene), where the concentration of NPB declined while the concentration of Alq₃ was increased gradually in the deposition process. The device exhibited a maximum emission of 49,300 cd/m² at a destroy voltage of 35 V and a maximum efficiency of 7.96 cd/A at 10 V, respectively. The efficiency improves twofold in comparison with the conventional doped devices. Meanwhile, the device exhibited superior operational stability with a half-life time of 1000 h at a starting luminance of 1000 cd/m² by a constant current driver.