共查询到19条相似文献,搜索用时 93 毫秒
1.
不久前,我们报导了以TPD为空穴传输层,Alq为电子传输兼发光层的双层薄膜电致发光器件,在定电流密度6mA/cm2连续驱动下,初始亮度106cd/m2下降至一半亮度的时间为120小时,而继续操作500小时,亮度仍有38cd/m2[1]。在这篇文章中,我们将报道一个在上述器件的空穴传输层TPD中掺杂而构成的新器件。这个新器件发光亮度和效率比原器件增加了50%,而稳定性增加了近10倍,初始亮度165cd/m2的半亮度寿命达1200小时。 相似文献
2.
金属/有机界面势垒对单层有机电致发光器件发光效率的影响 总被引:3,自引:2,他引:1
基于高场下电荷的注入过程及激子的解离和复合过程,建立了单层有机发光器件电致发光(EL)效率的理论模型。计算表明:(1)当金属/有机界面势垒高度大于0.3eV时,器件的EL效率很低,降低金属/有机界面势垒可以显著提高器件的EL效率;(2)在较低偏压下,注入过程对器件的电致发光效率起主要作用,但在高偏压下复合过程起支配作用。这一模型可以阐明注入和复合过程对有机发光器件EL效率的影响,对选择发光材料、优化器件结构和提高器件EL效率具有指导意义。 相似文献
3.
4.
基于紧束缚模型和格林函数方法,研究了有机磁体晶格扰动和侧基自旋取向扰动对金属/有机磁体/金属三明治结构有机自旋器件自旋极化输运特性的影响.计算结果表明:晶格扰动的存在降低了器件的起始偏压,减小了导通电流,并使得电流-电压曲线的量子台阶效应不再显著,扰动不太强时电流仍呈现较高的自旋极化率;而侧基自旋取向扰动减小了体系的自旋劈裂,增加了器件的起始偏压,低偏压下随着扰动的增强器件电流及其自旋极化率明显降低.进一步模拟了温度对器件自旋极化输运的影响.
关键词:
有机自旋电子学
有机磁体
自旋极化输运
自旋过滤 相似文献
5.
6.
7.
制备了常规有机发光二极管ITO/NPD/Alq3/LiF/Al,测量了该器件发光的磁场效应.发现尽管在1T范围内的磁场对发光层Alq3的光致发光没有影响,但磁场作用下器件的电致发光(MEL)却呈现出明显的磁效应,且MEL与器件的偏压有很强的依赖关系:在小偏压时,随着磁场的增加MEL是单调递增,且在大小约为40kA/m的磁场下达到饱和,之后即使磁场增大到约1T 的情况下也没有变化;但当偏压变大时,MEL则呈现先增加,在40kA/m处达到峰值后却又减弱,而且偏压越大该MEL的减弱则越明显.对所观察到的实验结果进行了定形解释,即三线态激子相互淬灭产生单线态激子和三线态激子与器件中的非平衡载流子相互作用是此效应的物理机理.
关键词:
有机发光
磁场效应
激子淬灭 相似文献
8.
有机薄膜电致发光器件结构与发光特性的研究 总被引:4,自引:0,他引:4
从有机电致发光薄膜的发光机理出发,通过以Alq薄膜器件、PVK为空穴传输层和Alq为发光层的双层 及PVK掺荧光材料Perylene的双层薄膜器件的研制,从器件的电致姚谱、电流密度-电压特性、亮度-电压特性的曲线的测试结果,计算分析了器件的流明效率、量子效率,并对有机薄膜电致发光器件的结构与发光特性之间的关系进行研究,利用能级理论分析了器件的姚特性随器件的结构不同所具有的规律。实验表明,加入PVK 相似文献
9.
10.
半导体量子点(QDs)具有发光效率高和发光波长可调等特点。采用胶体CdSe QDs作电致发光器件的有源材料,TPD(N,N′-biphenyl-N,N′-bis-(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine)作空穴传输层,ZnS作电子传输层,研究了有机/无机复合发光器件ITO/TPD/CdSe QDs/ZnS/Ag的电致发光特性。TPD和CdSe QDs薄膜采用旋涂方法、ZnS薄膜采用磁控溅射方法沉积,器件表面平整。CdSe QDs的光致发光和电致发光谱峰位波长均位于~580 nm,属于量子点的带边激子发光。我们与以前的ITO/ZnS/CdSe QDs/ZnS/Ag发光器件结构进行了对比,发现新的器件结构的电致发光谱没有观察到QDs表面态的发光,而且新器件的发光强度是ITO/ZnS/CdSe QDs/ZnS/Ag结构的~10倍。发光效率的提高归因于碰撞激发与载流子注入两种发光机制并存的结果:一方面电子经过ZnS 层加速后,碰撞激发CdSe QDs发光;另一方面,空穴从TPD层注入CdSe QDs 与QDs中激发的电子复合发光。我们进一步研究了ZnS电子加速层厚度对发光特性的影响,选择ZnS薄膜的厚度分别是80,120 和160 nm,发现随着ZnS层厚度增大,器件启亮电压升高,EL强度增大,但是击穿电压降低。EL峰位随着ZnS厚度的减小发生明显蓝移,对上述实验现象进行了机理解释。 相似文献
11.
12.
The purpose of this paper is to provide general information about basic physical processes involved in organic electroluminescence
and to present the main parameters and advantages of organic light emitting devices (OLEDs). 相似文献
13.
构建了基于n-ZnO纳米线/p-Si异质结的紫外发光二极管.ZnO纳米线准阵列采用水热法生长于重掺p型Si片上.此法简易,反应温度低,易于大规模生产;其产物ZnO纳米线结晶良好,以c轴为优势取向,光激发下的紫外荧光发射很强.二极管的电学接触采用聚合物填充的In阴极或以氧化铟锡(ITO)玻璃紧压形成阴极.它们的I-V特性体现出良好的二极管性质.在正向偏置电压驱动下,构建的发光二极管可稳定发射波长在387nm的较强的近紫外光和较弱的绿光.
关键词:
ZnO纳米线
异质结
电致发光
水热法 相似文献
14.
Electroluminescence enhancement in ultraviolet organic light‐emitting diode with graded hole‐injection and ‐transporting structure
下载免费PDF全文
![点击此处可从《固体物理学:研究快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Xiaowen Zhang Bingjie Mo Fengjiao You Xiujuan Zhou Liming Liu Honghang Wang Bin Wei 《固体物理学:研究快报》2015,9(6):353-357
Electroluminescent intensity and external quantum efficiency (EQE) in ultraviolet organic light‐emitting diodes (UV OLEDs) have been remarkably enhanced by using a graded hole‐injection and ‐transporting (HIT) structure of MoO3/N,N ′‐bis(naphthalen‐1‐yl)‐N,N ′‐bis(phenyl)‐benzidine/MoO3/4,4′‐bis(carbazol‐9‐yl)biphenyl (CBP). The graded‐HIT based UV OLED shows superior short‐wavelength emis‐ sion with spectral peak of ~410 nm, maximum electroluminescent intensity of 2.2 mW/cm2 at 215 mA/cm2 and an EQE of 0.72% at 5.5 mA/cm2. Impedance spectroscopy is employed to clarify the enhanced hole‐injection and ‐transporting capacity of the graded‐HIT structure. Our results provide a simple and effective approach for constructing efficient UV OLEDs. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
15.
研究了新型高效蓝色掺杂剂EBDP的电致发光性能. 分别以EBDP为掺杂剂制备了结构为氧化铟 锡(ITO)/酞菁铜(CuPc)/N,N′-二(1-萘基)-N,N′-二苯基-1,1′-联苯-4-4′-二胺(NPB)/2- 叔丁基-9,10-二-(2-萘基)蒽(TBADN):EBDP/8-羟基喹啉铝(Alq3)/LiF/Al 与ITO /CuPc/NPB/TBADN:EBDP: 4-二氰亚甲基-2-叔丁基-6-(1,1,7,7-四甲基久咯呢定基-9-烯基)- 4H-吡喃/Alq3
关键词:
有机电致发光
蓝色掺杂剂
蓝色电致发光器件
白色电致发光器件 相似文献
16.
《中国科学:物理学 力学 天文学(英文版)》2010,(1)
The DCM dye doped organic electroluminescence devices with structure of ITO/NPB/Alq 3 : DCM/Alq 3 /LiF/Al were fabricated. From 15 K to room temperature, the magnetic field dependent of electroluminescence (MEL) of devices was investigated. Our observations indicated that the MEL is composed of two effects in different regimes: a low field (0≤B≤40 mT) effect and a high field (B 40 mT) effect. For undoped devices, the low field effect exhibits a rapid rising with the increasing field, and the high field effect shows a slow increase and gradually saturates at room temperature. For doped devices, the low field rapid increase is also present, whereas the high field effect displays a decrease with the increasing field. The larger the injection current is, the more apparent the high field decrease is. In addition, the doped device demonstrates less temperature dependence of the high field effect than undoped device, although the undoped devices also present high field decrease of electroluminescence at low temperatures (T≤150 K). Based on the energy level trapping effect due to dye doping and magnetic field modulated triplet exciton annihilation, the experimental results are carefully explained. 相似文献
17.
Crystallized 4,7‐diphyenyl‐1,10‐phenanthroline (BPhen) films deposited by convenient vacuum thermal evaporation technique have been found to be an efficient means to extract the substrate wave guided light in organic light emitting diodes (OLEDs). The optimized BPhen film working as organic scattering layer was successfully used with OLEDs for light outcoupling efficiency improvement. Enhancement of 26%, 15% and 6% in efficiency of the blue, green and red OLEDs were obtained, respectively. The achievement was found to be advantageous in terms of simplicity of fabrication method and feasibility for large area OLED applications. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
18.
Abstract Hydrogenated amorphous silicon nitride-based heterojunction pin diode was electroformed under sufficiently high forward bias stress leading to its instant nanocrystallization at room temperature. In order to investigate the origin of the accompanying bright visible light emission, current-voltage and electroluminescence (EL) characteristics of the electroformed diode were scanned over temperature. Electrical transport mechanism was analysed in the low, medium and high electric field regimes. Temperature and field dependence of thermal activation energy were discussed. EL characteristics were studied using the spectral energy distribution and the injection current dependence of its intensity. Thermal quenching data of EL and photoluminescence intensities were compared. Finally, the relationship between the electrical transport and luminescence phenomena was attempted to be interpreted within the frame of a self-consistent model. 相似文献
19.
Effect of surface treatment of GaN based light emitting diode wafers on the leakage current of light emitting diode devices
下载免费PDF全文
![点击此处可从《中国物理 B》网站下载免费的PDF全文](/ch/ext_images/free.gif)
To form low-resistance Ohmic contact to p-type GaN,
InGaN/GaN multiple quantum well light emitting diode wafers are
treated with boiled aqua regia prior to Ni/Au (5~nm/5~nm) film
deposition. The surface morphology of wafers and the current--voltage
characteristics of fabricated light emitting diode devices are
investigated. It is shown that surface treatment with boiled
aqua regia could effectively remove oxide from the surface of the p-GaN
layer, and reveal defect-pits whose density is almost the same as
the screw dislocation density estimated by x-ray rocking curve
measurement. It suggests that the metal atoms of the Ni/Au transparent
electrode of light emitting diode devices may diffuse into the p-GaN
layer along threading dislocation lines and form additional leakage
current channels. Therefore, the surface treatment time with boiled
aqua regia should not be too long so as to avoid the increase of
threading dislocation-induced leakage current and the degradation of
electrical properties of light emitting diodes. 相似文献