激基复合物基高性能荧光有机发光二极管的研究

发布时间：2018-01-14 01:13

本文关键词：激基复合物基高性能荧光有机发光二极管的研究　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：有机发光二极管(Organic Light-Emitting Diode,OLED)已逐渐从实验室研发阶段开始向商业化应用阶段转化,但目前高效率的OLED几乎都采用磷光材料制的,磷光材料价格昂贵,且高效率、高稳定性蓝色磷光材料的短缺限制了磷光OLED的发展。热活化延迟荧光(Thermally Activated Delayed Fluorescence,TADF)材料因其具有无重金属、价格低廉及理论上100%激子利用率等优势,成为时下的一个研究热点。TADF发光体的一个分支——TADF激基复合物因其具有材料选择广泛、宽光谱等优势,近年来作为主体或发光体在OLED中得到广泛研究,并得到快速发展。但TADF激基复合物OLED的工作机理尚不完善,TADF激基复合物在单色光及白光荧光OLED的器件性能也有待于进一步提高。针对上述问题,本论文的主要研究内容如下:1.采用TCTA作为给体材料、3P-T2T作为受体材料,分别进行蒸镀,实现了具有TADF特性的分层界面激基复合物(TCTA/3P-T2T);进一步,将橙光发射的Rubrene掺入3P-T2T层,并优化Rubrene在3P-T2T中的掺杂浓度,实现了从激基复合物TCTA/3P-T2T到掺杂剂Rubrene的有效能量传递。通过简单的器件结构制备了基于Rubrene发射的高效率橙光荧光OLED。在优化的掺杂浓度1.5%下,器件实现的最大电流效率、功率效率和外量子效率分别为25.3cd/a、22.6lm/w和8.1%。高效率的实现归因于激基复合物tcta/3pt-2t的tadf特性,这使得激基复合物的三线态激子发生有效的反向系间窜越,进而实现了从激基复合物到掺杂剂的高效能量传递。与此同时,优化的1.5%掺杂浓度也有效抑制了发生在激基复合物和掺杂剂三线激发态之间的dexter能量传递过程。2.采用mcp作为给体材料、po-t2t作为受体材料,将给受体材料按1:1的比例共蒸,制备了具有tadf特性的蓝光发射激基复合物(mcp:3p-t2t);进一步,将橙光发射的荧光材料rubrene掺杂到该tadf激基复合物主体中,优化rubrene的掺杂浓度,实现蓝光激基复合物主体向rubrene的不完全能量传递,获得高效率、高色稳定性的荧光白光oled。在优化的掺杂浓度1.6%下,白光oled实现了最大的电流效率、功率效率和外量子效率,分别为14.2cd/a,12.8lm/w和4.9%。同时,器件实现了高的色稳定性,在4v,6v和8v的电压下,其cie坐标分别为(0.384,0.439),(0.384,0.440)和(0.383,0.441)。高效率的实现归因于激基复合物主体三线态激子的反向系间窜越和到掺杂剂的有效能量传递;而白光发射光谱高的色稳定性则归因于载流子从传输层到发光层的无势垒注入、载流子在发光层平衡地传输和复合以及宽的载流子复合区域。3.为了进一步简化白光oled的器件结构,提高白光oled的显色指数(colorrenderingindex,cri),采用发光光谱较宽的m-mtdata:tpbi及m-mtdata/bepp2激基复合物的黄绿光发射,同时结合电子传输材料Bepp2自身的蓝光发射,在两种激基复合物基OLED的电子传输层一侧引入TCTA激子阻挡层,通过对TCTA厚度细致的优化,实现了激基复合物和Bepp2的同时发光,获得了基于激基复合物发射的超简单、高显色指数的白光OLED。其中,基于m-MTDATA:TPBi共掺杂复合物荧光白光OLED的CRI值达到90,最大电流效率和功率效率分别达到9.3 cd/A和8.9 lm/W;基于m-MTDATA/Bepp2界面激基复合物荧光白光OLED的CRI值达到88,整个器件只用了三种有机材料,器件结构更加简单。这对开发结构简单、高CRI白光OLED具有很好的指导意义。
[Abstract]:Organic light emitting diode (Organic Light-Emitting Diode, OLED) has gradually from the stage of laboratory research and development began to transform to the commercial application stage, but the high efficiency OLED almost all of the phosphorescent materials, phosphorescent material is expensive, high efficiency and high stability, the shortage of blue phosphorescent materials limits the development of phosphorescent OLED. The activation of delayed fluorescence (Thermally Activated Delayed Fluorescence, TADF) materials because of its low price and no heavy metals, 100% theoretical exciton utilization and other advantages, become a TADF Electroplex branch of a research hotspot nowadays.TADF illuminant because of its wide selection of materials, wide spectrum and other advantages, in recent years as the main or light has been widely studied in OLED, and obtained rapid development. But the working mechanism of TADF Electroplex OLED is not perfect, the TADF exciplex complex in monochromatic light The performance of the device and white fluorescent OLED can be further improved. Aiming at the above problems, the main research contents of this thesis are as follows: 1. using TCTA as donor material, 3P-T2T as the receptor material, respectively, evaporation, realized the hierarchical interface of Electroplex with the characteristics of TADF (TCTA/3P-T2T); further, the orange light the launch of Rubrene doped 3P-T2T layer, and optimize the concentration of Rubrene in 3P-T2T, realize the transfer from exciplex TCTA/3P-T2T to energy efficient dopant Rubrene. Through the simple device structure was prepared based on high efficiency fluorescent OLED. Rubrene orange light emission in 1.5% under the optimum doping concentration, the maximum current efficiency device, power efficiency and external quantum efficiency were 25.3cd/a, TADF characteristics are attributed to the exciplex tcta/3pt-2t 22.6lm/w and 8.1%. with high efficiency, which makes the exciplex complex three Excitons reverse effective intersystem crossing, and then realize the transfer from exciplex to high energy dopant. At the same time, 1.5% optimized doping concentrations also can effectively inhibit the occurrence between the exciplex and dopant three line excited Dexter energy transfer process using MCP as to.2. body material, po-t2t as the receptor material, will give the recipient material according to the proportion of 1:1 co evaporation, with the characteristics of TADF emission of Electroplex prepared (mcp:3p-t2t); further, doped fluorescent material rubrene orange light emission to the TADF exciplex complex subject, optimizing the doping concentration of rubrene the blue Electroplex subject to incomplete energy transfer, rubrene efficiency, high color stability of fluorescent white oled. in 1.6% under the optimum doping concentration, white OLED achieved the maximum current efficiency, power efficiency and quantity The sub efficiency, respectively 14.2cd/a, 12.8lm/w and 4.9%. at the same time, the device realizes high color stability, 4V, voltage 6V and 8V, the CIE coordinates are (0.384,0.439), (0.384,0.440) and (0.383,0.441). High efficiency implementation of inverse system is attributed to the exciplex body three triplet excitons. Intersystem crossing and effective energy transfer and dopant; white light emission spectra of high color stability is attributed to barrier free into the carrier from the transport layer to the light emitting layer, a light-emitting layer carrier in a balanced transmission and composite and wide carrier composite.3. device in order to further simplify the structure of white OLED, the color index white OLED (colorrenderingindex, CRI), the emission spectrum of a wide m-mtdata:tpbi and m-mtdata/bepp2 exciplex emission combined with yellow green light emission, electron transport material, Bepp2's blue, in two kinds of exciplex The introduction of OLED compounds based on one side of the electron transport layer TCTA exciton blocking layer, by optimizing the detailed TCTA thickness, while the exciplex and Bepp2 emission was realized, obtained based on exciplex emission of super simple, high color index of white light OLED. which Co doped m-MTDATA:TPBi composite fluorescent white OLED based on the CRI value reached 90, the maximum current efficiency and power efficiency are respectively 9.3 cd/A and 8.9 lm/W; m-MTDATA/Bepp2 interface exciplex fluorescence white OLED based on the CRI value reached 88, the device is only three kinds of organic materials, the device structure is more simple. This paper has the advantages of simple structure, which is of great significance in high CRI white OLED.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN383.1

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