【作者】 谢文法；

【导师】 刘式墉；

【作者基本信息】 吉林大学 ， 微电子学与固体电子学， 2004， 博士

【摘要】 有机电致发光显示器件具有重量轻、成本低、视角宽、响应速度快、主动发光、发光亮度和发光效率高、能实现全色显示等优点，备受科学界和产业界的广泛重视。特别是C. W. Tang 于1987 年首次报道了可以在低电压工作的具有高发光亮度的有机电致发光器件以来，有机电致发光器件的研究工作有了更快速的发展。近十余年里，有机电致发光器件已经逐渐成为多学科交叉的高技术含量的前沿课题。白光有机发光器件不仅能够制作白光显示器件而且还能够与彩膜相结合制作全色显示器件，还可用作液晶显示的背光源，甚至用于照明。在1994年J. Kido 等人报道了有机电致白光器件以后，关于这方面的研究广泛地开展起来。本文中作者采用不同的材料制作了几种不同结构的白光器件，并详细研究了其光电特性。 2003年，Tsuji等首次将DCM1薄层(10?)引入到白光器件中制备了非掺杂型白光器件，然而此器件的最大亮度只有1000 cd/m2，器件的效率也未报道，我们通过分析DCM1层厚度对结构为ITO/NPB/DCM1/Alq3/LiF/Al的的器件亮度、效率的影响，认为Tsuji报道的白光器件亮度、效率低的原因在于DCM1层的厚度太厚而引起的荧光淬灭效应，基于以上的认识，我们制备了含DCM1超薄层的白光器件，器件的结构为ITO/NPB/DCM1/DPVBi/Alq3/LiF/Al，其中DCM1的厚度为0.05 nm，通过改变DPVBi的厚度可以和容易的调整器件的发光谱，我们获得了最大效率为1.74 lm/W，最大亮度为3750 cd/m2的白光器件，当电压从4 V变化到15 V时，器件的色坐标从(0.36, 0.38)变化到(0.30, 0.32)，都很接近白光等能点(0.33, 0.33)。此器件的特点在于首次在白光器件中使用了超薄的DCM1层，使得由于DCM1引起的浓度淬灭效应降到最低，从而提高了器件的效率。为了进一步提高非掺杂型器件的亮度和效率，我们首次将高效率的荧光染料rubrene引入到白光器件中，rubrene通常是作为掺杂剂使用的，日本学者<WP=134>Matsumura系统研究了rubrene超薄层的发光特性，制备了结构为ITO/TPD/rubrene/Alq3/ Mg:Al的黄光器件，通过研究rubrene层的厚度及位置对器件性能的影响，从而得出结论rubrene超薄层具有俘获空穴的能力，插入在TPD和Alq3之间时的效率最高。我们利用rubrene的独特特点，将其引入到白光器件中，制备了结构为ITO/NPB/rubrene/DPVBi/Alq3/LiF/Al的非掺杂型白光器件，器件的最大效率可达3.18 lm/W，在12 V的驱动电压下，亮度高达达17910 cd/m2，此外这个器件有一个非常好的特性就是当亮度从100变化到10000 cd/m2时器件的色坐标从(0.294, 0.320)变化到(0.298, 0.324)，几乎没有什么变化。此器件的性能在非掺杂型白光器件中处于领先地位。由于在磷光材料中单重态和三重态激子都可以通过辐射复合发光，所以在理论上它的发光效率是荧光材料的4倍，我们将高效率的红光[Ir(piq)2(acac)]及绿光[Ir(ppy)3]磷光掺杂染料同时掺入到同一个母体TPBI中，通过调整掺杂剂的浓度，并结合NPB的蓝光发射得到了高效率的白光发光器件，此器件的最大效率可达15.3 cd/A，最大亮度达33000 cd/m2，当电压从5 V变化到18 V时，色坐标从(0.44, 0.44)变化到(0.29, 0.34)基本处于白光区。此器件的特点在于利用红、绿两种比较常用的材料同时掺入到具有空穴阻挡和电子传输能力的母体中，从而在一个器件中同时实现红、绿及蓝光的发射从而得到白光发射，避免了使用比较稀有的蓝光磷光材料和与其相匹配的母体材料，同时又可以保持较高的发光效率且降低了器件的制备成本，器件的性能在国内已报道的白光器件中处于领先地位。此外作者还作了一些其他有机发光器件方面的研究，例如，(1)利用可变入射角椭圆偏振测量技术，测量了Alq3，NPB，CuPc，Rubrene等有机薄膜的光学常数和光学带隙，首次系统地给出了1-5 eV范围内多种有机发光材料的光学常数，并推导出了各种材料的光学带隙，在此基础上作者首次研究了膜层厚度对器件出射光透射率的影响；(2)研究了SnO2薄层对有机发光器件性能的影响，当将SnO2薄层置于Al阴极与Alq3发光层之间，器件的最大效率比没有插入SnO2的器件提高了近3倍，当将SnO2薄层置于ITO阳极与NPB层之间时，器件的最大效率是没有插入SnO2层的器件的1.6倍。我们认为器件效率的提高是因为SnO2层的存在平衡了载流子的注入。更多还原

【Abstract】 AbstractOrganic Light Emitting Devices (OLEDs) have attracted intensive interests from the fields of science and industrial for the merits of light weight, low cost, broad visual angle, fast response speed, active emitting, high brightness, high efficiency, availability for full color display, etc. The research works in this field gained rapid development especially after 1987 when C.W.Tang for the first time reported the high brightness OLED at low operating voltage. In recent ten years or so, OLED has become a project on the cutting-edge of scientific research that relates to many intercrossed branches of science and advanced technology.White organic light-emitting devices (WOLEDs) can be used in not only white displays but also full color displays combined with color filters, backlights for liquid crystal displays and even illumination light sources. The research works in this field gained rapid development especially after 1984 when J. Kido reported the WOLEDs. In this thesis, we introduce some different structure WOLEDs with different materials, and study the characteristics of these devices.Tsuji et al introduces a 10 ? DCM1 thin film to the WOLEDs and fabricated the non-doped WOLED in 2003. However, the maximum luminance of the devices can only reach 1000 cd/m2, and they also did not report the efficiency of the devices. We studied the effect of the DCM1 thickness on the luminance and efficiency of the devices whose structure is ITO/NPB/DCM1/Alq3/LiF/Al, and we think that the low-efficiency and -luminance of the WOLEDs fabricated by Tsuji et al is attributed to so-called concentration quenching. Thus, we fabricated the WOLEDs with an ultrathin DCM1 layer. The structure of the device is ITO/NPB/DCM1/DPVBi/Alq3/LiF/Al and the thickness of the DCM1 is 0.5 ?. The EL spectrum of the device can be adjusted by changing the thickness of DPVBi. As a result, we obtained the WOLEDs whose maximum efficiency and luminance are1.74 lm/W and 3750 cd/m2, respectively. And the chromaticity coordinates, varying from (0.36, 0.38) to (0.30, 0.32) with increasing forward bias from 4 to 15V, are well within the white region. The characteristic of the device is to use the DCM1 ultrathin <WP=136>layer in the device, which lowers the effect of the concentration quench. And as a result, the efficiency of the device is improved.In order to further improve the luminance, efficiency and chromaticity coordinates of the non-doped-type WOLEDs, we introduce the high-efficiency fluorescent dye rubrene to the non-doped WOLEDs. Usually, rubrene is used as a dopant. Matsumura et al studied the EL properties of the ultrathin rubrene. They studied the effect of the thickness and site on the performance of the device whose structure is ITO/TPD/rubrene/Alq3/Mg:Al, and obtained the results that the rubrene layer can capture hole and when rubrene inserted between TPD and Alq3, the devices has the maximum efficiency. Thus, we fabricated the non-doped type WOLEDs with an ultrathin rubrene using the unique property of the rubrene. The devices has the following structure: ITO/NPB/ rubrene/DPVBi/Alq3/LiF/Al. Bright white light, over 10000 cd/m2, was successfully obtained at a low drive voltage of ~10V. The highest power efficiency is 3.18 lm/W at 4V, and stable 1931 Commision International de L’Eclairage coordinates are obtained for luminance ranging from 100 to 20 000 cd/m2 (at ~12 V). The performance of this WOLED is superior in the non-doped type WOLEDs.By employing a phosphorescent dye where both singlet and triplet excited states participate, the OLED internal efficiency can, in principle, be increased to nearly quadruple that of a fluorescent one. Efficient white emission from the mixing of red emission from the bis(1-(phenyl)isoquinoline)iridium(III)acetylanetonate [Ir(piq)2(acac)], green emission from the fac tris (2-phenylpyridine) iridium [Ir(ppy)3], and blue emission from the N,N′-bis-(1-naphthyl)-N,N′-diphenyl-1, 1′-biph-enyl-4,4′-diamine (NPB) is obtained. Ir(piq)2(acac) and Ir(ppy)3 are co-doped into 2,2’,2’’-(1,3,5-phenyl更多还原