基于溶液加工小分子材料发光层的有机—无机复合发光器件的研究

发布时间：2018-01-18 00:31

本文关键词：基于溶液加工小分子材料发光层的有机—无机复合发光器件的研究　出处：《西南大学》2016年硕士论文　论文类型：学位论文

【摘要】：有机-无机复合发光器件(Hybrid organic-inorganic light-emitting diodes:HyLEDs)采用高功函数金属顶阳极和稳定性良好的载流子传输材料,克服了传统结构器件中低功函数金属阴极和电子注入层稳定性差,以及导电聚合物空穴注入层同铟锡氧化物(ITO)电极之间的相互作用等对器件存储和驱动稳定性产生影响的不利因素,有着很好的应用前景。金属氧化物具有高载流子迁移率,宽带隙,易合成,性质稳定,无毒环保等优点,被广泛作为HyLEDs的载流子传输层。磷光材料能同时利用单线态和三线态发光,是提高HyLEDs发光效率的有效途径。本文主要研究了溶液加工小分子材料发光层薄膜的形貌和光电特性,制备高效率的有机-无机复合单色光和白光器件器件,主要研究工作包括以下几个方面:(1)研究了以不同溶剂制备的小分子材料发光层薄膜的特性。分别以氯苯和四氢呋喃(THF)为溶剂制备TCTA和OXD-7(质量比为1:1)的发光层薄膜,部分以THF为溶剂制备的薄膜通过热处理,并且制备了真空蒸镀的TCTA:OXD-7薄膜作为对比研究。通过溶液加工的TCTA:OXD-7薄膜平整、均匀,具有和真空热蒸镀的薄膜具有相近的表面形貌,粗糙度RMS分别为0.29、0.29、0.26及0.23 nm。制备了单极性空穴和电子器件来研究薄膜的载流子传输特性,发现不同薄膜的单电子和单空穴器件电流密度的变化规律相同,都满足ITHFIannealedICBIevaporated,真空蒸镀的薄膜电子和空穴的迁移率最高。我们用椭圆偏振光谱仪测量了不同薄膜的折射率,折射率的变化规律和电流密度的变化规律一致,表明薄膜对电子和空穴传输能力与薄膜的堆积密度有关,堆积密度越大,则载流子传输特性越好。(2)以氯苯为溶剂,TCTA:OXD-7为主体材料,PhFIrPic、Ir(btp)_2(acac)、PO-01分别为蓝色、红色和黄色磷光材料制备了高效率的蓝光、红光和黄光有机-无机复合发光器件。研究了主体材料TCTA和OXD-7不同比例对基于PhFirPic有机无机复合蓝光器件效率的影响,发现随着OXD-7浓度的增加,发光层中电子的传输能力增强,载流子传输更加平衡,器件的发光效率提高,当TCTA:OXD-7为1:1时器件的发光性能最好。PhFIrPic掺杂浓度为20%时,蓝光器件的发光效率最高,最大亮度效率为38.5 cd A-1,最大外量子效率为18.9%。在此基础上,制备基于溶液加工小分子发光层的有机-无机复合红、黄光器件,最大外量子效率分别为10.2%和14.6%。器件的发光效率均较以往报道的有机-无机发光器件有明显提高。器件的发光效率随电流的增加而降低,其特征电流为136.1,83.1和219.4 mA cm-2,这主要是由于采用小分子双主体材料,器件具有较宽的载流子复合区域,降低了三线激发态-三线激发态湮灭和三线激发态-极化子相互作用对器件发光效率的影响。(3)在高效率蓝光、黄光和红光有机-无机复合器件的基础上,制备了高效率的有机-无机复合白光器件。首先研究了TCTA:OXD-7为主体材料,PhFIrPic为蓝光材料(掺杂浓度20%),PO-01或Ir(BT)_2(acac)为和黄光材料的有机无机复合白光器,研究了PO-01和Ir(BT)_2(acac)浓度对器件特性的影响,发现黄光材料的浓度器件的电流-电压特性的影响较小,器件发光光谱中黄光的发光强度随PO-01(或Ir(BT)_2(acac))浓度的增加而增加。其中,发光层为TCTA:OXD-7:20%PhFIrPic:0.4%PO-01的白光器件最大外量子效率和功率效率为15.0%和30.0 lm W-1,器件在1000 cd m-2时器件的外量子效率和功率效率分别为14.7%和20.6 lm W-1,是目前报道的发光效率较高的有机-无机复合白光器件。器件发光色度为(0.33,0.44),不随驱动电流的变化而变化,器件的显色指数为63。为了提高白光器件的显色指数,在发光层中掺入了红光材料Ir(btp)_2(acac),这样白光器件的发光光谱实现了可见光范围全覆盖,器件的显色指数CRI提高到了71,器件的最大外量子效率为10.9%。器件具有高的发光效率主要归因于小分子双主体材料拥有较高的三线态能量和平衡的载流子传输特性,能够有效地将三线激发态限制在磷光材料上,获得高效的磷光发射,以及小分子材料在聚乙烯亚胺上良好的成膜特性和较高的载流子传输特性。
[Abstract]:Organic inorganic composite light emitting device (Hybrid organic-inorganic light-emitting diodes:HyLEDs) with high work function metal anode and the top carrier transport material with good stability, to overcome the traditional structure of the device of low work function metal cathode and the electron injection layer and a conductive polymer stability, hole injection layer of indium tin oxide (ITO) electrode interaction on the storage devices and unfavorable factors influence the driving stability, has a good application prospect. Metal oxides with high carrier mobility, wide band gap, easy synthesis, properties of stability, non-toxic environmental protection and other advantages, is widely used as a carrier transport layer HyLEDs. The phosphorescent material can utilize both singlet and triplet emission is three. Effective way to improve the luminous efficiency of HyLEDs. This paper mainly studies the morphology of thin film light-emitting layer solution processed small molecule materials and photoelectric characteristics The preparation of high efficiency, the organic-inorganic composite light and white light devices, the main research work includes the following aspects: (1) characteristics of the light emitting layer film small molecular materials with different solvents were prepared respectively. Using chlorobenzene and tetrahydrofuran (THF) as solvent for preparation of TCTA and OXD-7 (mass ratio 1:1) luminescent film by THF thin films prepared by solvent thermal treatment, and TCTA:OXD-7 films were prepared by vacuum evaporation as a comparative study. Through the TCTA:OXD-7 film formation, solution processed thin films with uniform and vacuum thermal evaporation with similar surface morphology, roughness RMS carrier transmission characteristics were 0.29,0.29,0.26 and 0.23 nm. for unipolar hole and electron devices to study film preparation, found the changes of different films and single hole single electron device current density are the same, with the ITHFIannealedIC BIevaporated, transfer film electron and hole vacuum evaporation rate. We use ellipsometry to measure refractive index of different film rate, consistent with the variation of refractive index variation and current density, show that the film and film of electron and hole transport ability of the bulk density, bulk density increasing, while the carrier transport the better characteristics. (2) using chlorobenzene as solvent, TCTA:OXD-7 as the main material, PhFIrPic, Ir (BTP) _2 (ACAC, PO-01) were prepared with high efficiency blue light blue, red and yellow phosphorescent materials, red light and yellow light organic inorganic composite light-emitting devices. The main materials of TCTA and OXD-7 in different proportions the influence of PhFirPic organic inorganic composite blue devices based on efficiency, found that with the increase of OXD-7 concentration, light transmission capacity enhancement layer electronic transmission carrier, more balanced, to improve the luminous efficiency of the device, When the TCTA:OXD-7 is 1:1 the best luminescent properties of.PhFIrPic doped concentration device is 20%, the highest luminous efficiency of blue devices, the maximum luminance efficiency of 38.5 CD A-1, maximum external quantum efficiency of 18.9%. based on the preparation of solution processing of small molecules based on luminescent organic-inorganic composite layer of red, yellow OLEDs, the maximum the quantum efficiency of 10.2% and 14.6%. respectively, the luminous efficiency of the device are compared with the previously reported inorganic organic light-emitting devices have improved significantly. The luminous efficiency of the device decreases with the increase of the current, the current characteristics of 136.1,83.1 and 219.4 mA cm-2, which is mainly due to the small molecular double main material, device with wide carrier composite the three line, reduce the influence of excited state - three line and three line annihilation excited excited state - polaron interaction on the luminescent efficiency. (3) in the high efficiency blue light, red light organic - Huang Guanghe Based on the inorganic composite device, high efficiency organic inorganic composite light emitting devices were prepared. Firstly, TCTA:OXD-7 as the main material, PhFIrPic as blue light emitting materials (doping 20%), PO-01 (BT) or Ir _2 (ACAC) and yellow light material of organic and inorganic composite white, on PO-01 and Ir (BT) _2 (ACAC) concentration effect on the device characteristics, found little effect of current concentration device yellow light material voltage characteristics, the luminous intensity of luminescence spectra of yellow light with PO-01 (or Ir (BT) _2 (ACAC)) concentration increases. The light emitting layer is TCTA:OXD-7:20%PhFIrPic:0.4%PO-01 the white light device maximum external quantum efficiency and power efficiency of 15% LM and 30 W-1, external quantum efficiency and power efficiency of the device in 1000 CD m-2 devices were 14.7% LM and 20.6 W-1, is a light emitting organic inorganic composite with high efficiency white light is reported . chromaticity for (0.33,0.44), and not change with the changes of driving current, the color rendering index of the device was 63. in order to improve the color rendering index of white light devices, in the light-emitting layer doped with Ir (BTP) _2 red materials (ACAC), the luminescence spectra of white light emitting device realizes the visible range. Full coverage, the color rendering index of CRI device is increased to 71, the maximum external quantum efficiency of the device is a 10.9%. device has a high luminous efficiency is mainly attributed to the small molecular double main material has a high three line state energy and the balance of the carrier transport characteristics, can effectively be three line excited state restrictions on phosphorescent materials. To obtain efficient phosphorescent emission, carrier transport characteristics and small molecular materials in polyethyleneimine on good film-forming property and high.

【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN383.1

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