空穴缓冲层2T-NATA厚度对OLED器件性能的影响

在有机电致发光器件中,载流子的注入和匹配水平直接影响着器件性能.在器件中引入空穴缓冲传输层2T-NATA,能够有效改善阳极与有机层的接触,改变有机层中的势垒分布,提高载流子的注入和平衡水平,使激子复合率得到有效改善,从而使器件发光特性大幅提高.     

有机电致发光器件中载流子的动态分析

通过对有机电致发光器件中电子和空穴进行动态分析,对其发光机理进行详细研究与探讨,得出以下结论:有机电致发光材料的载流子传输性能影响着载流子在发光层禁带中的分配和载流子复合区域位置;有机电致发光器件的工作过程分为载流子陷阱填充和载流子复合发光两个主要过程.     

有机电致发光器件中载流子的动态分析

通过对有机电致发光器件中电子和空穴进行动态分析,对其发光机理进行详细研究与探讨,得出以下结论:有机电致发光材料的载流子传输性能影响着载流子在发光层禁带中的分配和载流子复合区域位置;有机电致发光器件的工作过程分为载流子陷阱填充和载流子复合发光两个主要过程.     

蒽掺杂对8—羟基啉喹铝器件电学和发光特性的影响

1、引言自 Tang 和 Van Slyke 的研究报导以后,人们对有机材料 TFEL 器件的研究日趋重视。这类 EL 器件通常由有机发光层和有机载流子输运层构成,前者的作用是电致发光,后者则有选择地输运电子或空穴,并将其有效地注入到发光层内。     

蓝光OLED器件载流子复合区域的研究

制备了结构为ITO／NPB／BAlq／Alq/Mg：Ag的有机电致发光器件(OLED),研究了有机层厚度对器件载流子复合区域的影响。实验结果表明当改变各有机层厚度时,OLED器件的电致发光光谱将发生从绿光到蓝光的变化。经分析这是由于各有机层电场强度变化影响了空穴和电子的隧穿几率,从而导致载流子的复合区域发生改变而发射不同颜色的光。     

有机电致发光器件载流子注入效率的研究

文章从电极材料、结构、处理方法等角度出发,详细介绍了提高有机电致发光（ＥＬ）器件载流子注入效率的研究现状。     

OLED功能层界面电荷累积对器件性能的影响

有机电致发光器件(OLED)的任意两相邻功能层交界面上的电荷在电场作用下会发生电荷极化和电荷累积,从而给载流子的注入带来一定的影响,电荷累积的多少和累积的种类都与这两功能层材料有直接的关系.从多层电介质交界面的全电流密度和电场应满足的基本关系出发,利用初始条件和最终状态的边界条件,探讨了有机电致发光器件的任意两相邻功能层界面电荷累积的基本规律,分析了这种界面的电荷累积对器件性能的影响.结果表明,适当调节相邻功能层界面累积的电荷,可以平衡载流子的注入,有利于提高器件的效率.     

有机LED的界面与载流子注入

介绍了有机电致发光器件中金属／有机界面和有机／有机界面与载流子注入的关系。     

空穴缓冲层CuPc对有机电致发光器件特性的影响

采用旋涂和真空蒸发沉积工艺制备了结构分别为ITO/PVK:TPD/Alq3/Al和ITO/PVK:TPD/LiBq4/Alq3/Al的绿色和蓝色有机电致发光器件(OLED),并研究了空穴缓冲层CuPc对OLED特性的影响.结果发现:对于绿色OLED,CuPc的加入提高了器件的电流和亮度,改善了器件的性能;而对于蓝色OLED,CuPc的加入则加剧了载流子的不平衡注入,导致器件性能恶化.这表明空穴缓冲层CuPc对不同结构OLED的特性具有不同的影响,并通过器件的能级结构对此进行了解释.     

有机电致发光薄膜的电流输运机理的分析

用TPD作空穴传输层、8－羟基喹啉锌作发光层,制备了有机薄膜器件,测量了其电致发光特性。分析了该器件的电流输运机理,认为该有机薄膜器件在电致发光时流过器件的电流受热电子注入效应、空间电荷限制效应、隧穿效及器件电阻效应的影响。     

Influences of Injection Barrier and Mobility on Recombination Rate and Zone in OLEDs

The luminous efficiency of organic light-emitting devices depends on the recombination probability of electrons injected at the cathode and holes at the anode. A theoretical model to calculate the distribution of current densities and the recombination rate in organic single layer devices is presented taking into account the charge injection process at each electrode, charge transport and recombination in organic layer. The calculated results indicate that efficient single-layer devices are possible by adjusting the barrier heights at two electrodes and the carrier mobilities. Lowering the barrier heights can improve the electroluminescent（EL） efficiency pronouncedly in many cases, and efficient devices are still possible using an ohmic contact to inject the low mobility carrier, and a contact limited contact to inject the high mobility carrier. All in all, high EL efficiency needs to consider sufficient recombination, enough injected carriers and well transport.     

Carrier radiation distribution in organic light-emitting diodes

This paper is based on the analysis of white organic electroluminescent device electroluminescent spectrum to explain the regular pattern of carrier radiation distribution.It has proved electron that is injected from cathode is satisfied with the regularity of radiation distribution on the organic emitting layer.This radiation distribution is related to several factors,such as electron injection capabilities,applied electrical field intensity,carrier mobility,etc.The older instruction design is ITO/2-TNATA/NPB/ADN:DCJTB:TBPe/Alq3/cathode.Get to change electron injector capabilities through using different cathode and also find electroluminescent spectrum to produce significant changes.Simultaneously,electron radiation quantity has some limitation,and electroluminescent spectrum reflects that spectral intensity does not change anymore when the ratio of cathode dopant to a saturated state on the organic emitting layer.It also shows the same spectrum variational phenomenon while changing the applied electrical field intensity.To put forward of the carrier radiation distribution is good for organic light emitting diode (OLED) luminescence properties analysis and research.     

Multicolor organic electroluminescent device utilizingvapor-deposited fluorescent dye films

Multicolor-emitting organic electroluminescent (EL) diodes have been realized utilizing a vapor-deposited multilayer structure. Two types of layer structure have been employed to realize multicolor emission. One type has a three-layer structure (Type I) to emit two different colors; the other type has five layers (Type II) to emit three different colors. The Type I devices contain 1,2,3,4,5-pentaphenyl-1,3-cyclopentadiene (PPCP), 8-hydroxyquinoline aluminum (Alq₃), or N,N'-bis(2,5-di-tert-butylphenyl)-3,4,9,10-perylene dicarboximide (BPPC) as blue, green, or red light-emitting layers, respectively, and N,N'-diphenyl-N,N'-(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) as carrier blocking layer. The emission colors are changed by applying opposite polarity of electric field in the Type I devices, and, in the Type II devices, by applying different strength and polarity of electric field. The mechanism of the emission color change is discussed by the carrier injection mechanism and recombination process in the multilayer devices     

Organic Light‐Emitting Transistors Containing a Laterally Arranged Heterojunction

An approach to produce organic light‐emitting transistors (OLETs) containing a laterally arranged heterojunction structure, which minimizes exciton quenching at the metal electrodes, is described. This device configuration provides an organic light‐emitting diode (OLED) structure where the anode (source) electrode, hole‐transport material (field‐effect material), light‐emitting material, and cathode (drain) electrode are laterally arranged, thus offering a chance to control the electroluminescent intensity by changing the gate bias. Pentacene and tris(8‐quinolinolato)aluminum (Alq₃) are employed as the field‐effect and light‐emitting materials, respectively. The laterally arranged heterojunction structures are achieved by successively inclined deposition of the field‐effect and light‐emitting materials. After deposition of pentacene, a narrow gap of about 10–20 nm between the drain electrode and pentacene was obtained, thereby creating an opportunity to fabricate a laterally arranged heterojunction. In the OLETs, unsymmetrical source and drain electrodes, that is, Au and LiF/Al ones, are used to ensure efficient injection of holes and electrons. Visible‐light emission from OLETs is observed under ambient atmosphere. This result is ascribed to efficient carrier injection and transport, formation of a heterojunction, as well as good luminescence from the organic emissive layer. The device structure serves as an excellent model system for OLETs and demonstrates a general concept of adjusting the charge‐carrier injection and transport, as well as the electroluminescent properties, by forming laterally arranged heterojunctions.     

有机电致发光材料的研究进展

有机电致发光(OEL)是近年来国际上的一个研究热点。有机电致发光器件具有低压驱动、高亮度、高效率以及能实现大面积彩色显示等优点。介绍了有机电致发光材料特别是金属配合物和聚合物材料的国内外研究进展，并在此基础上探讨了分子结构与发光性能的关系．     

n型聚合物掺杂p型聚合物单层电致发光器件

成功制备了可溶性n型聚合物PPQ掺杂的可溶性p型聚合物PDDOPV的单层发光器件。与具有相同厚度的纯PDDOPV的单层器件相比，起亮电压从4.5V降低到2.6V；在电压相同的条件下，掺杂的单层器件的电流和纯PDDOPV的单层器件在同一个数量级，但亮度和发光效率均高出1个数量级以上。在10V时，掺杂器件与未掺杂器件的电流、亮度和发光效率的比值分别是1.95,30.9和16.0。掺杂器件亮度和发光效率的大幅提高被归因于在PDDOPV中掺杂PPQ降低了少子的注入势垒，提高了少子注入水平。这一结果表明，在可溶性p型聚合物中掺杂可溶性n型聚合物是提高器件性能的有效方法。     

Luminescent Efficiency in Single-layer Organic Electrophosphorescent Devices

Based on the charge injection and recombination processes and the triplet-triplet annihilation process, a model to calculate the electro.luminescent（EL） efficiency is presented. The influences of the applied electric field on the injection efficiency, recombination efficiency and electroluminescent efficiency are discussed. It is found that： （1） The injection efficiency is increasing while the recombination efficiency is decreasing with the applied electric field increasing. （2） The EL efficiency is enhanced at low electric field slowly but is decreasing at high electric field with the increase of applied voltage. （3） The EL efficiency is decreasing with the increase of the host-guest molecular distance （R）. So, it is concluded that the EL efficiency in single-layer organic electrophosphorescent devices is dominated by injection efficiency at lower electric field and recombination efficiency at higher electric field.     

Highly Efficient Three Primary Color Organic Single‐Crystal Light‐Emitting Devices with Balanced Carrier Injection and Transport

Organic single crystals have a great potential in the field of organic optoelectronics because of their advantages of high carrier mobility and high thermal stability. However, the application of the organic single crystals in light‐emitting devices (OLEDs) has been limited by single‐layered structure with unbalanced carrier injection and transport. Here, fabrication of a multilayered‐structure crystal‐based OLED constitutes a major step toward balanced carrier injection and transport by introducing an anodic buffer layer and electron transport layer into the device structure. Three primary color single‐crystal‐based OLEDs based on the multilayered structure and molecular doping exhibit a maximum luminance and current efficiency of 820 cd cm^?2 and 0.9 cd A^?1, respectively, which are the highest performance to date for organic single‐crystal‐based OLEDs. This work paves the way toward high‐performance organic optoelectronic devices based on the organic single crystals.     

Control of the Interface between Tris(8-quinolinolato) Aluminum and Aluminum Layers in an Organic Electroluminescent devices

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Photoresponse and electroluminescence of silicon-〈porous silicon〉-〈chemically deposited metal〉 structures

Photoelectric and electroluminescent properties of silicon-〈porous silicon〉 structures with chemically deposited metal contacts were investigated. The large specific surface area of the contact and selective metal deposition only on the macrocrystalline elements of the structure provide better photoelectric performance of the photodiodes compared to the structures with evaporated contacts, especially in the short-wavelength spectral range. The obtained electroluminescence spectra are explained by metal-silicon barrier properties under forward bias and by double carrier injection into nanocrystallites under reverse bias.