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1.
合成并研究了聚(9-丁基芴)的电致发光和光致发光特性.通过控制其浓度,可获得从黄到蓝不同颜色的发光,并分析了发光的性质. 相似文献
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染料掺杂的红色有机薄膜电致发光器件 总被引:2,自引:3,他引:2
近年来 ,有机发光二极管 (OL EDs)得到了广泛深入的研究[1~ 3] 。研究工作主要集中在探索新的有机荧光材料、载流子注入和输运材料 ,以及器件的新结构 ,力求得到发光效率高和稳定性好的各种不同颜色的发光。从目前的研究来看 ,尽管蓝色和绿色发光材料的效率已经足够高到实用 ,但红色发光材料仍然存在问题 ,对红色发光进行研究是非常必要的。有两条实现红色发光的途径 :掺杂能发红光的染料和用稀土离子配合物作基质或激活剂。利用能量传递的原理 ,在有机基质材料中掺杂荧光染料是获得高效、长寿命和所希望发光颜色的一种有效而简单的方法… 相似文献
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利用不同比例的烷基芴-噻吩无规共聚物,制备了聚合物薄膜发光二极管,研究了不同噻吩含量对器件电致发射光谱的影响,发现改变共聚噻吩含量可有效调节器件发光谱色。通过研究器件在增加电流密度、升温老化处理后的光谱演变发现,相应器件的谱色稳定性在噻吩含量达到5%-10%后相当稳定,噻吩含量10%的共聚芴所制备的器件在电流密度达到520mA/cm^2或经过高达160℃温度老化后发光谱色无变化。初步探讨了共聚芴荧光谱色随噻吩含量变化的机制,认为无规共聚已使得两种共轭单元对应的能带结构发生相当程度的杂化。而对器件谱色随电流升高、温度老化表现出的优异稳定性,则认为源于低带隙材料的引入破坏了聚芴分子链的共平面结构,提高了形成激基缔合物的能垒。 相似文献
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本文综述了基于电致发光效应的光学电压传感器机理、分类及其主要特性,分析总结了此类传感器的研究现状及其存在的主要问题,同时提出未来研究课题的建议。电致发光型电压传感器的主要优点在于不需要载波光源,因而可以有效避免以往光学电压器中工作光源性能不稳定所引起的传感器性能变化;此外,此类电压传感器结构简单、体积小、重量轻、成本低,可以实现较高的性能价格比。今后研究的主要问题包括合理选择电压传感材料与器件、提高传感器的温度和湿度稳定性等。电致发光型电压传感器在电力工业和航空航天等领域的科学研究与实验中将具有广泛的应用前景。 相似文献
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发展了基于稳定金属电极的阴极界面材料,对促进聚合物电致发光器件的产业化进程具有重要意义。侧链含磷酸酯功能基团的聚芴衍生物(PF-EP)是一种极性聚合物中性材料,能溶于乙醇等醇类溶剂,非常适合制备多层溶液加工型发光器件。除此之外,它结合稳定的金属Al电极能实现有效电子注入。本文以PF-EP在绿光聚芴发光器件中的应用为例,详细对比分析了两种基于PF-EP的阴极电极结构(PF-EP/LiF/Al和PF-EP/Al)的器件EL性能。结果显示,PF-EP/LiF/Al阴极结构具有更优异的电子注入能力。基于单电子器件和X射线光电子能谱,本文对这一高效电子注入结构的注入能力和注入机理进行了探讨。 相似文献
7.
研究了新型的芴-咔唑共聚物(PFC)与聚乙烯咔唑(PVK)掺杂体系的光致发光和电致发光特性.制备了结构分别为indium-tin-oxide(ITO)/PVK:PFC/bathocuproine(BCP)/tris-(8-hydroxylquinoline)-aluminum (Alq3) /Mg:Ag,ITO/PFC/BCP/Alq3/Mg∶Ag和ITO/PVK/BCP/Alq3/Mg∶Ag的三种有机电致发光器件.对器件的光电特性进行了测试.结果表明,掺杂体系中的PVK有效地抑制了固态膜中PFC激基缔合物的形成.掺杂器件在不同的外加电场作用下发生发光层位置的移动,通过调节外加电场,可以获得从绿光到蓝光的可见光发射.当外加电压大于7V时,掺杂器件的蓝色发光亮度达到1650cd/m2,推测其中可能存在从PVK到PFC的能量传递过程. 相似文献
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CdxZn1-xS:SmF3的红色薄膜电致发光 总被引:1,自引:0,他引:1
本文首次报道了用CdxZn1-xS替代ZnS作为基质,改进SmF3的TFEL的实验;通过适当地在基质中掺杂CdS,在一定程度上提高了SmF3的TFEL发光亮度;分析了CdxZn1-xS基质中Cd含量对SmF3的TFEL的影响,探讨了发光亮度提高的原因. 相似文献
11.
Optimization of a poly (p-phenylene benzobisoxazole)-based light-emitting device with a complex cathode structure 下载免费PDF全文
In this work,we report the preparation of a series of electroluminescent(EL)devices based on a high-performance polymer,poly(p-phenylene benzobisoxazole)(PBO),and their optoelectronic properties,which have been rarely explored.The device structure is optimised using a complex cathode structure of tris-(8-hydoxyquinoline)aluminium(Alq3)/LiF/Al.By tuning the thickness of the Alq3layer,we improve the device efficiency dramatically in an optimized condition.Further analysis reveals that the Alq3layer in the complex cathode structure acts as a hole blocker in addition to its electron-injection role.A green light emission with a maximum brightness of 8.7×103cd/m2and a moderate current efficiency of 4.8 cd/A is obtained.These values are the highest ever reported for PBO devices.The high operational stability demonstrated by the present device makes it a promising tool for display and lighting applications.A new material is added to the selection of polymers used in this field up to now. 相似文献
12.
《Current Applied Physics》2015,15(3):248-252
Red phosphors Ca9Bi1-x(PO4)7:xEu3+ (x = 0.06, 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80 and 1.00) were synthesized by a conventional solid-state reaction (SSR) route. The X-ray diffraction patterns, photoluminescence spectra, ultraviolet–visible reflection spectroscopy, decay time and the International Commission on Illumination (CIE) chromaticity coordinates of these compounds were characterized and analyzed. The Eu-doped Ca9Bi(PO4)7 phosphors exhibited strong red luminescence which peaks located at 615 nm due to the 5D0→7F2 electric dipole transition of Eu3+ ions after excitation at 393 nm. Ultraviolet–visible spectra indicated that the band-gap of Ca9Bi0.30(PO4)7:0.70Eu3+ is larger than that of Ca9Bi(PO4)7. The results indicate that the phosphor Ca9Bi0.30(PO4)7:0.70Eu3+ can be a suitable red-emitting phosphor candidate for LEDs. 相似文献
13.
从聚合物/电极界面修饰的角度对基于饱和红光聚合物PFO-SeBT(9,9-二辛基芴与4,7-二硒吩-2,1,3-苯并噻二唑的无规共聚物)的发光二极管的性能进行了改进,通过采用CsF/Al阴极并优化CsF的厚度以及在PFO-SeBT1/阳极界面插入聚乙烯基咔唑(PVK)层,使器件的最大电致发光外量子效率达到1.79%,比采用低功函数的金属Ba/Al阴极器件的效率提高了两倍多.器件的性能得以改善的原因是CsF/Al阴极能有效提高电子注入能力以及PVK层对电子的阻挡作用.
关键词:
聚合物发光二极管
聚合物/电极界面
CsF/Al阴极
电子注入 相似文献
14.
Performance improvement of InGaN blue light-emitting diodes with several kinds of electron-blocking layers 下载免费PDF全文
The performance of InGaN blue light-emitting diodes(LEDs) with different kinds of electron-blocking layers is investigated numerically.We compare the simulated emission spectra,electron and hole concentrations,energy band diagrams,electrostatic fields,and internal quantum efficiencies of the LEDs.The LED using AlGaN with gradually increasing Al content from 0% to 20% as the electron-blocking layer(EBL) has a strong spectrum intensity,mitigates efficiency droop,and possesses higher output power compared with the LEDs with the other three types of EBLs.These advantages could be because of the lower electron leakage current and more effective hole injection.The optical performance of the specifically designed LED is also improved in the case of large injection current. 相似文献
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This work demonstrates the fabrication of a bright blue organic light-emitting diode (BOLED) with good color purity using 4,4′-bis(2,2-diphenylvinyl)-1,1′-biphenyl (DPVBi) and bathocuproine (BCP) as the emitting layer (EML) and the hole-blocking layer (HBL), respectively. Devices were prepared by vacuum deposition on indium tin oxide (ITO)-glass substrates. The thickness of DPVBi used in the OLED has an important effect on color and efficiency. The blue luminescence is maximal at 7670 cd/m2 when 13 V is applied and the BCP thickness is 2 nm. The CIE coordinate at a luminance of 7670 cd/m2 is (0.165, 0.173). Furthermore, the current efficiency is maximum at 4.25 cd/A when 9 V is applied. 相似文献
16.
Performance improvement of blue InGaN light-emitting diodes with a specially designed n-AlGaN hole blocking layer 下载免费PDF全文
Blue InGaN light-emitting diodes (LEDs) with a conventional electron blocking layer (EBL), a common n-AlGaN hole blocking layer (HBL), and an n-AlGaN HBL with gradual Al composition are investigated numerically, which involves analyses of the carrier concentration in the active region, energy band diagram, electrostatic field, and internal quantum efficiency (IQE). The results indicate that LEDs with an n-AlGaN HBL with gradual Al composition exhibit better hole injection efficiency, lower electron leakage, and a smaller electrostatic field in the active region than LEDs with a conventional p-AlGaN EBL or a common n-AlGaN HBL. Meanwhile, the efficiency droop is alleviated when an n-AlGaN HBL with gradual Al composition is used. 相似文献
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Performance improvement of blue InGaN light-emitting diodes with a specially designed n-AIGaN hole blocking layer 下载免费PDF全文
Blue InGaN light-emitting diodes (LEDs) with a conventional electron blocking layer (EBL), a common n-A1GaN hole blocking layer (HBL), and an n-A1GaN HBL with gradual A1 composition are investigated numerically, which involves analyses of the carrier concentration in the active region, energy band diagram, electrostatic field, and internal quantum efficiency (IQE). The results indicate that LEDs with an n-AIGaN HBL with gradual AI composition exhibit better hole injection efficiency, lower electron leakage, and a smaller electrostatic field in the active region than LEDs with a conven tional p-A1GaN EBL or a common n-A1GaN HBL. Meanwhile, the efficiency droop is alleviated when an n-A1GaN HBL with gradual A1 composition is used. 相似文献
18.
Denghui Xu Zhenbo Deng Xiufang Li Zheng Chen Zhaoyue Lv 《Physica E: Low-dimensional Systems and Nanostructures》2008,40(9):2999-3003
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). 相似文献
19.
L. S. Lepnev A. A. Vaschenko A. G. Vitukhnovsky S. V. Eliseeva O. V. Kotova N. P. Kuzmina 《Journal of Russian Laser Research》2008,29(5):497-503
Organic light emitting diodes (OLEDs) based on zinc complexes with tetradentate Schiff bases — ZnSB [H2SB =H2Sal1, H2Sal2 (derivatives of salicylic aldehyde); H2MO1, H2MO2 (derivatives of o-vanillin)] display reversible and irreversible electroluminescence (EL) instability. The reversible
instability occurs after switching voltage on and the irreversible instability produced by UV light irradiation, heating,
and aging under the ambient conditions. In view of the results obtained, the first type of instability is associated with
the trap filling processes and the second type appearing at heating is possibly attributed to the changes in the interface
domains. Recommendations for the evaporation and capsulation conditions are provided. 相似文献
20.
The electroluminescence (EL) characteristics of phosphorescent organic light-emitting diodes (OLEDs) with an undoped bis(1,2-dipheny1-1H-benzoimidazole) iridium (acetylacetonate) [(pbi)2Ir(acac)] emissive layer (EML) of various film thicknesses were studied. The results showed that the intensity of green light emission decreased rapidly with the increasing thickness of (pbi)2Ir(acac), which was relevant to the triplet excimer emission. It suggested that the concentration quenching of monomer emission in the undoped (pbi)2Ir(acac) film was mainly due to the formation of triplet excimer and partly due to the triplet-triplet annihilation (TTA) and triplet-polaron annihilation (TPA). A green OLED with a maximum luminance of 26,531 cd/m2, a current efficiency of 36.2 cd/A, and a power efficiency of 32.4 lm/W was obtained, when the triplet excimer emission was eliminated. Moreover, the white OLED with low efficiency roll-off was realized due to the broadened recombination zone and reduced quenching effects in the EML when no electron blocking layer was employed. 相似文献