基于非掺杂式电荷生成层的结构设计以及叠层OLED的制备研究

发布时间：2018-03-08 21:06

本文选题：叠层　切入点：有机电致发光器件　出处：《太原理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：叠层有机电致发光器件（Tandem Organic Light-emitting diodes, TOLED）是指将多个独立的发光单元通过电荷生成层连接，在外加电场的作用下电荷生成层产生的电子和空穴分别注入到相邻发光单元的电子、空穴传输层中，与来自阳极和阴极的空穴、电子在发光层中复合，从而实现更高的亮度和电流效率。与传统的单发光层器件相比，TOLED具有高亮度、高电流效率和长寿命等优点。尽管电荷生成层的研究已经取得较大发展，但仍然存在诸多问题需要解决，如传统掺杂式的电荷生成层使叠层器件的制备更复杂、电荷生成层中金属氧化物通过高温蒸镀影响器件性能等。对此，本论文主要围绕制备高效的电荷生成层展开，以实现高性能的叠层OLED器件。主要研究内容如下： 1.以LiF/Al/C60/m-MTDATA作为电荷生成层，首先验证了电荷的产生发生在C60/m-MTDATA的界面处，从能级结构上解释了电荷生成层产生电荷的过程。此外，通过一系列倒置型器件，对电荷生成层的厚度和蒸镀速率进行了优化，Al和C60的厚度均为7nm，Al的蒸镀速率为1/s。最终采用最优的电荷生成层制备了TOLED器件，与单层器件和以LiF(1nm)/Al(7nm)/CuPc(7nm)/m-MTDATA (10nm)作为电荷生成层的叠层器件相比，TOLED器件的最大电流效率和功率效率分别达到48.1cd/A和19.3lm/W，是单层器件的2.98和1.65倍，且是另一种TOLED器件的1.2和1.13倍。 2.基于发光单元NPB/Alq3、采用LiF/Al/HAT-CN/m-MTDATA作为电荷生成层制备叠层器件。此电荷生成层均选择蒸镀温度较低的有机材料，且该电荷生成层在可见光范围内的透光率高达90%以上，且有优异的电荷产生和分离能力。通过调节HAT-CN和Al的厚度，发现电荷生成层厚度的不同会对电荷的产生和分离有影响，当HAT-CN和Al的厚度分别为9nm和5nm，电荷生成层具有较好的电荷产生和分离能力。最后以优化好的电荷生成层制备了叠层器件，和简单堆叠器件、单层器件进行了对比，叠层器件的最大电流效率与功率效率分别高达4.84cd/A,1.79lm/W，是单层器件的2.2倍和1.6倍。 3.将Ag应用在电荷生成层中，制备了结构为LiF/Ag/HAT-CN/m-MTDATA的电荷生成层。由于Ag不仅具有较好的导电性，而且当Ag的厚度为1-2nm时，它可表现出局部等离子体振动，即对可见光的吸收，有助于提高电荷生成层的性能。以NPB/Alq3为发光单元制备了基于该电荷生成层的叠层器件，通过Ag厚度的优化考察了叠层器件的性能，当Ag厚度为1nm时，叠层器件最大电流效率可达6.76cd/A，，是单层器件的2.7倍。此外，我们分别制备了基于上述最优的三种电荷生成层LiF/Al/C60/m-MTDATA、LiF/Al/HAT-CN/m-MTDATA、LiF/Ag/HAT-CN/m-MTDATA的蓝光叠层器件，考察了三种器件的电致发光性能，为以后制备不同性能的叠层器件提供了参考。
[Abstract]:The stacked organic electroluminescent device Tandem Organic Light-emitting diodes( Tole) refers to the connection of several independent light-emitting cells through a charge-generating layer, and the electrons and holes produced by the charge-generating layer are injected into the electrons of the adjacent light-emitting cells respectively under the action of an external electric field. In the hole transport layer, electrons are recombined in the luminescent layer with holes from the anode and cathode to achieve higher luminance and current efficiency. Although the research of charge generation layer has made great progress, but there are still many problems to be solved, such as the traditional doped charge generation layer makes the fabrication of laminated devices more complex. Metal oxides in the charge generation layer affect the device performance through high temperature evaporation. In this paper, we mainly focus on the preparation of high efficiency charge generation layer to achieve high performance stacked OLED devices. The main research contents are as follows:. 1. Using LiF/Al/C60/m-MTDATA as the charge generation layer, it is first verified that the charge generation occurs at the interface of C60 / m-MTDATA, and the process of charge generation in charge generation layer is explained from the energy level structure. In addition, through a series of inverted devices, The thickness of charge generation layer and the rate of evaporation plating are optimized. The thickness of Al and C 60 are both 7nmmAl and the rate of evaporation is 1 / s. Finally, the TOLED device is fabricated by using the optimal layer of charge generation. The maximum current efficiency and power efficiency of LiF(1nm)/Al(7nm)/CuPc(7nm)/m-MTDATA devices are 48.1 cm / A and 19.3lm / W respectively, 2.98 and 1.65 times of that of monolayer devices and 1.2and 1.13 times of that of another TOLED device. 2. Based on the light-emitting unit NPB / Alq3, LiF/Al/HAT-CN/m-MTDATA is used as the charge generation layer to fabricate the laminated devices. All of these layers choose organic materials with low evaporation temperature, and the transmittance of the charge forming layer is over 90% in the visible light range. By adjusting the thickness of HAT-CN and Al, it is found that the difference of the thickness of the charge formation layer has an effect on the generation and separation of charge. When the thickness of HAT-CN and Al are 9 nm and 5 nm, respectively, the charge generation layer has better charge generation and separation ability. Finally, the stacked devices are fabricated with the optimized charge generation layer, and compared with simple stacked devices and single layer devices. The maximum current efficiency and power efficiency of laminated devices are as high as 4.84 CD / A 1.79 m / r W, which is 2.2 times and 1.6 times higher than that of single-layer devices. 3. When Ag is applied to the charge generation layer, a charge forming layer with LiF/Ag/HAT-CN/m-MTDATA structure is prepared. Because Ag not only has good conductivity, but also exhibits local plasma vibration, that is, absorption of visible light, when Ag thickness is 1-2nm. In order to improve the performance of the charge generation layer, the laminated device based on the charge generation layer was fabricated by using NPB/Alq3 as the light-emitting unit. The performance of the laminated device was investigated by optimizing the Ag thickness. When the Ag thickness was 1 nm, the performance of the laminated device was investigated. The maximum current efficiency of the laminated devices can reach 6.76 cdr / A, 2.7 times that of the single-layer devices. In addition, we have fabricated LiF / Al / Al / Al / Al / HAT-CNDATA-LiF / CNAT-CNMTDATA-LiF / AgR / HAT-CNAT-CN-MTDATA based on the above three optimal charge generation layers, and investigated the electroluminescence properties of the three kinds of devices. It provides a reference for the fabrication of laminated devices with different properties.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN383.1

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