电压控制发光颜色的有机电致发光器件

基于空穴阻挡层BCP掺杂红光染料DCJTB的简单体系制备了一种电压调制发光颜色的有机电致发光二极管(OLED)。器件发光颜色随电压改变发生了从橙色到紫色的连续变化。通过不同层间的能级势垒对这种发光颜色改变的特性进行了合理化的解释。     

磷光染料共掺杂方法提高红光有机发光二极管性能的研究

通过两种不同红光磷光染料6％的PtOEP与7％的（btfmp）2Ir（acac）共掺同一基质中作为发光层，使有机电致发光器件的性能全面得到改善,共掺器件的最大效率达到了3．2cd／A，而单一染料6％的PtOEP或7％的（btfmp）2Ir（acac）掺杂器件的效率分别为1．8cd／A和2．9cd／A,另外，共掺杂器件表现出了更低的驱动电压，其效率在大电流下的衰降程度也大大降低,这些改善应归功于提高了发光层中总的掺杂浓度而没有引起相应高的浓度淬灭的结果。     

PtOEP掺杂Alq3有机发光器件的能量传递

研究了高效磷光染料八乙基卟啉铂(PtOEP)掺杂于主体材料八羟基喹啉铝(Alq3)体系中PtOEP、Alq3之间的能量传输机制.分别以PtOEP掺杂和未掺杂的Alq3膜作为发光层制作有机发光器件(OLED),改变掺杂浓度,检测器件电致发光(EL)光谱的变化.经分析,在5%、10%、20%三种掺杂浓度中,10%掺杂浓度能量传递效果最好.通过对掺杂和未掺杂器件电流密度-电压、亮度-电压数据检测,计算外量子效率,在低电流密度(《7mA/cm2)驱动下掺杂器件外量子效率是未掺杂器件的5倍.     

PtOEP掺杂A1q3有机发光器件的能量传递

研究了高效磷光染料八乙基卟啉铂（PtOEP）掺杂于主体材料八羟基喹啉铝（A1q3）体系中PtOEP、A1q3之间的能量传输机制。分别以PtOEP掺杂和未掺杂的A1q3膜作为发光层制作有机发光器件（OLED），改变掺杂浓度，检测器件电致发光（EL）光谱的变化。经分析，在5％、10％、20％三种掺杂浓度中，10％掺杂浓度能量传递效果最好。通过对掺杂和未掺杂器件电流密度-电压、亮度-电压数据检测，计算外量子效率，在低电流密度（≤7mA/cm^2）驱动下掺杂器件外量子效率是未掺杂器件的5倍。     

电压调节变色的有机薄膜电致发光器件

制备了结构为ＩＴＯ／ＳＡ／ＰＢＤ／Ａｌｑ３／Ａｌ的电压调制发光颜色的有机薄膜电致发光器件，研究了有机层厚度不同的器件的发光光谱随电压变化的性能，建立了器件的能级结构模型，并用这种模型解释了器件的电致发光性能。     

有机电致发光器件中染料掺杂类型的研究

采用对主体材料8-hydroxyquinoline aluminum（Alq3）掺杂的方法,通过对3种小分子荧光染料Dimetb-ylquinacridone（DMQA）、4-（Dicyanomethylene）-2-t-butyl-6-（1,1,7,7-tetramethyljulolidyl-9-enyl）-4H-pyran（DCJTB）、5,6,1l,12-tetraphenylnaphthacene（Rubrene）的研究,比较了其光致发光光谱和吸收光谱,利用Rorster能量传递（ET）理论和直接载流子俘获（DCT）理论对这3种材料作为掺杂染料的类型进行了讨论。研究表明,3种荧光染料同时具有F6rsterET类型和DCT类型掺杂剂的性质,并不只是一种单一类型的掺杂染料,由此推测大多数掺杂染料可能应同时属于此两种类型。     

基于调制电压滤波器的电压稳定性研究

提出一种低成本电压稳定方案,利用双调制开关电源滤器补偿方案,采用动态误差驱动驱动控制器以稳定负荷母线的电压。使用一种新的PWM开关的动态三环路控制器来稳定电压及提高电能质量,在三环路动态误差跟踪控制器驱动即是基于此控制理论。     

单发光层结构的白色有机电致发光器件的研究

在研究了合成并提纯的蓝光材料Liq和黄光染料Rubrene发光特性的基础上,采用高效的荧光染料Rubrene作为掺杂剂掺杂在母体材料Liq中,制备了单发光层结构的有机电致发光器件.当掺杂摩尔分数为1.0%时,器件得到了近白色发光(色度x=0.29,y=0.34),在驱动电压为24V 时,器件的亮度达到了2804cd/m2,在驱动电压为16V时,器件的效率达到了4.6cd/A.     

有机电致发光器件掺杂研究进展

有机电致发光器件(Organic light-emitting device,OLED)因具有成本低、主动发光、驱动电压低、响应速度快、视角宽及可柔性显示等诸多优势,在平板显示及固态照明领域受到广泛关注。但无论是用作显示还是照明,色彩的应用都是不可或缺的。制备不同颜色的发光器件,除可以使用各种颜色的有机材料外,利用荧光或磷光染料掺杂也是重要的方法。同时,这种方法也可以大大提高器件的量子效率。尤其从理论上来说,磷光OLED的内量子效率可以达到100%。从OLED的掺杂原理、荧光掺杂与磷光掺杂等方面阐述了OLED的研究进展。     

有机掺杂体系中的Frster能量传递及其在电致发光中的应用

给体的光致发光量子效率、受体的消光系数及给体的发射谱与受体的吸收光谱的重叠程度,这3个因素对给体与受体间的能量传递效率有重要影响,这对于扩大材料的选择范围,实现有机电致发光的全色显示有重要启示。研究发现在Alq3中掺杂DCM制得的器件很好地满足了这3个条件。本文从F rster能量传递的3个影响因素出发,对Alq3/DCM、TPD/Alq3等不同掺杂体系的光致发光、电致发光特性和能量传递效率等进行了讨论。     

基于N-苯基咔唑的红色有机电致发光材料

设计合成了一种N-苯基咔唑的衍生物:3-2-(3,3-二腈基亚甲基-5,5-二甲基-1-环己烯基)乙烯基-N-苯基-咔唑(PNCa-2CN).PNCa-2CN的甲醇溶液光致发光光谱和固体膜光致发光光谱峰值分别位于598nm和660nm.以PNCa-2CN作为红色发光材料掺杂在Alq3中,制备了结构为ITO/NPB/Alq3:PNCa-2CN(5%)/Alq3/Mg:Ag/Ag的具有较高发光效率的红色有机电致发光器件,器件的发光峰值为600nm,在外加20V直流电压时达到2372cd·m-2的发光亮度,100mA·cm-2和20mA·cm-2其亮度分别为323cd·m-2和64cd·m-2,器件最大流明效率达到1.3lm·W-1.     

Pentafluorophenoxy boron subphthalocyanine as a fluorescent dopant emitter in organic light emitting diodes

A fluorinated phenoxy boron subphthalocyanine (BsubPc) is shown to function as a fluorescent dopant emitter in small molecule organic light emitting diodes (OLEDs). Narrow electroluminescence (EL) emission with a full width at half-maximum of ～30 nm was observed regardless of the host used, indicating that this narrow EL is intrinsic to the BsubPc molecule. A bathochromic shift and the growth of a new EL peak at higher wavelengths with increasing doping concentration were found to be a result of molecular aggregation. Excitation of BsubPc by direct charge trapping as well as Fo?rster resonant energy transfer were shown using different host molecules. A maximum efficiency of 1.5 cd/A was achieved for a 4,4'-N,N'-dicarbazole-biphenyl (CBP) host.     

基于新型红色材料的有机发光二极管

对一种名为N，N－双－[4-2-(4-二氰甲烯基－6－甲基）－4H－吡喃－2－基]乙烯基]苯基苯胺的新型有机红色材料（BDCM）进行了薄膜发光行为的研究，此材料的一个三苯胺（给电子基）和两个二氰甲烯吡喃（受电子基）所形成的较好空间位阻和强荧光发射能力，使得其固体薄膜具有很高的红色荧光量子产率。所构成ITO／CuPc/DPPP/BDCM/Mg:Ag的红色薄膜电致发光器件，在外加19V直流电压时达到582cd/m^2的发光亮度，同时，此器件的发光色度具有不随所加电流密度变化而改变的特点，表明此材料有很好的电子传输和红色发射性能。     

Impacts of dopant concentration on the carrier transport and recombination dynamics in organic light emitting diodes

The carrier transport and recombination dynamics of organic light emitting diodes as a function of dopant concentration were studied. In the lightly-doped sample, a higher carrier mobility and better device performance were observed. Due to the aggregations in the highly-doped sample, carrier quenching as well as nonradiative recombination degraded the device performance. In addition, the observed decay rates and luminescence efficiencies of the doped samples could be used to calculate the radiative decay rate (κ_r) and nonradiative decay rate (κ_nr). With a higher dopant concentration, κ_r became lower and κ_nr was enhanced. It was found that the applied voltages, corresponding to equal κ_r and κ_nr, decreased with the dopant concentration. These demonstrate that the lightly-doped sample exhibits better luminescence efficiency than the highly-doped samples at all applied voltages and that all the doped samples exhibit peak luminescence efficiency at relatively low applied voltage, with luminescence efficiency decreasing for all the doped samples as the applied voltage is increased. The resulting recombination dynamics are correlated with the device characteristics and performance of the doped samples.     

Electroluminescence of organolanthanide based organic light emitting diodes

Recent advances in organolanthanide based organic light emitting diodes have lead to the demonstration of infra-red emitting devices. A silicon based organic light emitting diode exhibiting 1.53 μm electroluminescence at room temperature has also recently been reported. Furthermore, recent work has led to a clearer understanding of the quenching mechanisms in these organolanthanide based devices and suggests that the efficiencies obtained to date can be greatly improved.     

有机小分子电致磷光及发光机理研究进展

在过去10余年对小分子和聚合物电致发光器件的研究中,由于器件三线态激子能量没有得到充分的利用,使器件的内量子效率存在25%的理论极限,大大限制了其发光效率。为突破这一理论极限,在小分子主体材料中掺杂磷光染料制成电致磷光器件是近几年研究的热点,磷光染料的掺杂可以充分利用单线态和三线态激子,理论上器件的内量子效率可以达到100%。本文针对有机小分子电致磷光器件的发展、发光机理以及主客体分子间的能量传递等方面作了简明的讨论,指出了在器件设计时应该注意的一些问题。     

Study of thermal degradation of organic light emitting device structures by X-ray scattering

We report the process of thermal degradation of organic light emitting devices (OLEDs) having multilayered structure of [LiF/tris-(8-hydroxyquinoline) aluminum(Alq₃)/N,N′-Bis(naphthalen-1-yl)-N,N′-bis(phenyl)benzidine (NPB)/copper phthalocyanine (CuPc)/indium tin oxide (ITO)/SiO₂ on a glass] by synchrotron X-ray scattering. The results show that the thermally induced degradation process of OLED multilayers has undergone several evolutions due to thermal expansion of NPB, intermixing between NPB, Alq₃, and LiF layers, dewetting of NPB on CuPc, and crystallization of NPB and Alq₃ depending on the annealing temperature. The crystallization of NPB appears at 180 °C, much higher temperature than the glass transition temperature (T_g = 96 °C) of NPB. The results are also compared with the findings from the atomic force microscope (AFM) images.     

柔性有机薄膜电致发光显示材料及器件

有机薄膜电致发光显示器件(OLED)近年来得到了迅猛发展,是未来全固体平板式彩色显示器的重要候选者,其最大优势之一是可以制作成柔性显示器件。本文综述了柔性有机电致发光材料及器件的发展概况、工作原理与优缺点,目前制作此类器件中存在的困难及解决这些困难的有效措施。     

Investigation of defects in polyhedral oligomeric silsesquioxanes based organic light emitting diodes

We have investigated novel poly(p-phenylene vinylene) (PPV) derivative based organic light emitting diodes (OLEDs). We have used poly(2,3-diphenyl-1,4-phenylenevinylene) (DP-PPV) as an emitter in which an inorganic core of polyhedral oligomeric silsesquioxanes (POSS) have been incorporated. The hybrid structure obtained shows an improvement on the stability and an enhancement of electroluminescence properties. Charge-based deep level transient spectroscopy (Q-DLTS) has been used to study the defect states in indium-tin-oxide (ITO)/polyethylene dioxythiophene:polystyrene sulfonate (PEDOT:PSS)/POSS-DP-PPV/CaAl light emitting devices. Analysis of the Q-DLTS spectra obtained in devices, reveal at least six trap levels. The mean activation energies of traps are distributed in the range 0.3–0.5 eV within the band gap of the hybrid polymer and capture cross sections are of the order of 10¹⁶–10²⁰ cm². The trap densities are in the range of 10¹⁶–10¹⁷ cm^?3. Although the origin of these traps remains not clearly established, we suggest that the trap states with a large capture cross-section would likely to be originated from the inorganic part of hybrid material while those with lower capture cross-section would be related to its organic part.