一种新型铕配合物的有机电致发光性能

研究了一种新型的稀土金属铕配合物EuL₁L₂的光致发光和电致发光特性。将这种铕配合物掺杂到PVK:PBD中,制备成结构为ITO/PVK:PBD:EuL₁L₂/PBD/Alq₃/Mg:Ag/Ag的器件,对其电致发光性能进行研究,发现Eu³⁺离子和Alq₃的相对发光强度随PVK:PBD:EuL₁L₂和Alq₃之间的激子阻挡层PBD的厚度变化而变化,通过调节PBD的厚度,得到了色纯度较高的红色电致发光器件,其光谱具有显著的Eu³⁺离子的光谱特征。     

SYNTHESIS AND CHARACTERIZATI0N OF POLYMETHACRYLATES BEARING HETEROCYCLIC AZO GROUP AND MESOGENIC GROUP FOR NONLINEAR OPTICS

The methacrylate monomers bearing mesogenic group and heterocyclicazo dye have been synthesized. The monomeric dye was copolymerized with the mesogenicmonomer using a free radical initiator to produce polymers useful for nonlinear optics. Themonomers and polymers were characterized by IR, ~1H-NMR, and UV-Vis spectra. Theaverage molecular weight (M_w and M_n) of the polymers were determined by gel permeationchromatography. The thermal properties of the polymers such as thermal stability andphase transition behavior were studied by thermogravimetric analysis, differential thermalanalysis, polarizing optical microscope and X-ray diffractometer. The results demonstratethat the synthesized polymers are crystalline polymers at room temperature and no liquidcrystalline phases were observed for all of them.     

Improving efficiency of organic light-emitting devices by optimizing the LiF interlayer in the hole transport layer

The efficiency of organic light-emitting devices (OLEDs) based on N,N'-bis(1-naphthyl)-N,N'-diphenyl-N,1'-biphenyl-4,4'-diamine (NPB) (the hole transport layer) and tris(8-hydroxyquinoline) aluminum (Alq₃) (both emission and electron transport layers) is improved remarkably by inserting a LiF interlayer into the hole transport layer. This thin LiF interlayer can effectively influence electrical performance and significantly improve the current efficiency of the device. A device with an optimum LiF layer thickness at the optimum position in NPB exhibits a maximum current efficiency of 5.96 cd/A at 215.79 mA/cm², which is about 86% higher than that of an ordinary device (without a LiF interlayer, 3.2 cd/A). An explanation can be put forward that LiF in the NPB layer can block holes and balance the recombination of holes and electrons. The results may provide some valuable references for improving OLED current efficiency.     

Tandem white organic light-emitting diodes adopting a C60：rubrene charge generation layer

Organic bulk heterojunction fullerence(C60) doped 5, 6, 11, 12-tetraphenylnaphthacene(rubrene) as the high quality charge generation layer(CGL) with high transparency and superior charge generating capability for tandem organic light emitting diodes(OLEDs) is developed. This CGL shows excellent optical transparency about 90%, which can reduce the optical interference effect formed in tandem OLEDs. There is a stable white light emission including 468 nm and 500 nm peaks from the blue emitting layer and 620 nm peak from the red emitting layer in tandem white OLEDs. A high efficiency of about 17.4 cd/A and CIE coordinates of(0.40, 0.35) at 100 cd/m2 and(0.36, 0.34) at 1000 cd/m2 have been demonstrated by employing the developed CGL, respectively.     

色彩转换膜对白色有机电致发光光谱的影响

利用蓝色有机发光二极管激发荧光色彩转换膜的方法,制备了一种新型的白色有机电致发光器件。蓝色有机发光二极管的发光层采用4,4’-Bis(carbazol-9-yl)biphenyl(CBP)主体掺杂高效蓝色荧光染料N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylbenzenamine (N-BDAVBi)来制备。有机/无机复合色彩转换膜是将有机荧光颜料VQ-D25和无机荧光粉掺铈钇铝石榴石(YAG∶Ce3+)按一定的重量比均匀分散到-[CH₃CH₂COOCH₃]_n-(PMMA)中来制备。获得了色稳定性较高的白色有机电致发光器件。当驱动电压由6升至14 V时,器件光谱非常稳定且CIE色坐标仅从(0.354,0.304)变化到(0.357,0.312),其最高电流效率约为5.8 cd·A-1(4.35 mA·cm-2),最高亮度为16 800 cd·m-2(14 V)。     

优化反式平面钙钛矿太阳电池性能的简便方法——利用PEDOT:PSS与DMSO共混空穴传输层

优化界面接触、增强界面处载流子传输对于提高钙钛矿电池性能具有重要意义。本研究将适量二甲基亚砜（DMSO）添加到聚（3,4-乙烯二氧噻吩）-聚（苯乙烯磺酸盐）(PEDOT∶PSS)空穴传输层中,改善了空穴传输层的导电性和空穴传输特性,有效提高了反式平面钙钛矿太阳能电池光伏性能。短路电流(J_sc)从21.29 mA/cm²提高到22.15 mA/cm²,填充因子（FF）从76.35%提高到80.09%,转换效率（PCE）从16.02%提高到17.01%。薄膜与器件性能综合测试结果表明,DMSO的掺入使PEDOT∶PSS发生适度相分离,形成更好的PEDOT导电通道,增强了PEDOT∶PSS的导电特性。稳态光致发光光谱呈现出显著的荧光猝灭效应,也表明掺杂DMSO后PEDOT∶PSS的空穴提取能力得到提高,钙钛矿活性层与阳极之间的空穴传输更加顺畅,有助于实现高达80%以上的填充因子。本研究为改善反式平面钙钛矿太阳电池或有机太阳电池光伏性能提供了一种高效、简便的方法,具有很好的现实意义。     

插入电荷控制层对蓝色OLED发光性能的提高

用蓝色有机荧光材料N6,N6,N12,N12-tetrap-tolylchrysene-6,12-diamine(DNCA)作为发光层,在发光层中间以及发光层与电子传输层之间插入2-methyl-9,10-di(2-napthyl)anthracene(MADN)和9,10-di(2-naphthyl)anthracene(ADN)作为电荷控制层,制备了结构为ITO/NPB(40 nm)/DNCA(15 nm)/MADN(3nm)/DNCA(15 nm)/ADN(3 nm)/Bphen(30 nm)/LiF(0.8 nm)/Al(120 nm)的蓝色有机电致发光器件(OLED)。该器件的最大电流效率和最大亮度分别为5.6 cd/A和23 310 cd/m2。与传统的单发光层器件相比,最大电流效率和最大亮度分别提高了70%和87%。器件发光性能的提高可归结于两个电荷控制层在整个器件中的协同作用。第一电荷控制层MADN的作用主要是将发光层区域分成两个部分,从而扩大了激子在发光层中的复合区域;第二电荷控制层ADN可以有效地将空穴限制在发光层中,避免了激子在电子传输层中形成的无辐射跃迁从而提高了器件的发光性能。     

插入电荷控制层对蓝色OLED发光性能的提高

用蓝色有机荧光材料N⁶,N⁶,N¹²,N¹²-tetrap-tolylchrysene-6,12-diamine （DNCA）作为发光层,在发光层中间以及发光层与电子传输层之间插入2-methyl-9,10-di（2-napthyl）anthracene （MADN） 和9,10-di（2-naphthyl）anthracene （ADN） 作为电荷控制层,制备了结构为ITO/NPB（40 nm）/DNCA（15 nm）/MADN（3 nm）/DNCA（15 nm）/ADN（3 nm）/Bphen（30 nm）/LiF（0.8 nm）/Al（120 nm）的蓝色有机电致发光器件（OLED）。该器件的最大电流效率和最大亮度分别为5.6 cd/A和23 310 cd/m²。与传统的单发光层器件相比,最大电流效率和最大亮度分别提高了70%和87%。器件发光性能的提高可归结于两个电荷控制层在整个器件中的协同作用。第一电荷控制层MADN的作用主要是将发光层区域分成两个部分,从而扩大了激子在发光层中的复合区域;第二电荷控制层ADN可以有效地将空穴限制在发光层中,避免了激子在电子传输层中形成的无辐射跃迁从而提高了器件的发光性能。     

聚合物O-PPV的链间相互作用的研究

近年来,聚对苯乙炔(PPV)及其衍生物作为一类性能优良的电致发光材料而受到人们的广泛关注[1].这是因为聚合物发光材料能通过化学裁剪方法来改善发光效率、颜色、成膜性等特性.载流子形成激子以及激子的辐射和非辐射衰减过程向来是聚合物发光二极管(LEDs)发光的重要环节,因此研究聚合物的光物理过程对提高器件的发光特性是非常重要的.