低压高效的串联式有机电致发光器件的性能研究

发布时间：2018-05-09 09:02

本文选题：有机电致发光器件 + 缓冲层　；参考：《天津理工大学》2017年硕士论文

【摘要】：近年来,有机电致发光器件(OLED)在显示和照明领域有了长足的发展,而进一步提高器件的发光效率及稳定性仍是目前OLED在推进商品化进程中所面临的关键问题。串联结构的OLED器件与传统的OLED器件相比具有诸多优势,如:亮度高、电流效率高和稳定性较好等,因此受到了社会各界人士的青睐。但是串联OLED器件仍然存在启亮电压高、电流效率不能成倍提高等问题。本文先从单一发光单元的OLED器件入手,着重研究如何优化载流子的注入、传输及平衡复合,制备出高效的OLED器件;另一方面,依据复合电子缓冲层的结构,进一步设计出新颖的电荷产生层,并制备出低启亮电压、高效的串联OLED器件。具体的研究内容如下:1、首先,将碱金属氯化物NaCl薄层插入空穴传输层NPB中,通过调节NaCl薄层的厚度来调控注入到发光层中的空穴数量,有效地提高了OLED器件的电流效率,其中最优化器件的电流效率最大值为5.3 cd/A,比传统器件的电流效率(4.1 cd/A)提高了29.3%;然后,将TCNQ作为非掺杂型电子缓冲层,插入到电子传输层Bphen与阴极之间,通过优化TCNQ的厚度来提高电子的传输和注入能力。此外,TCNQ还可以改善阴极与与传输层之间的接触特性,从而使得器件的亮度、电流效率和功率效率依次增加了37.1%、50.8%和162.5%;最后,同样采用非掺杂的方法将NaCl薄层与金属Mg相结合作为器件的电子缓冲层,有效地平衡了注入到发光层中的空穴与电子,进而提高了器件的电流效率。其中最优化器件的电流效率最大值为6.9 cd/A,比传统器件的电流效率(4.1cd/A)提高了68.3%。2、基于上一章中的NaCl/Mg电子缓冲层可以有效改善电子的注入能力,构建了一种新颖的非掺杂型电荷产生层:NaCl/Mg/MoO_3/NPB。首先,通过制备单一电子传输型器件和单一空穴传输型器件,解释了电荷产生层的工作机理,并将此电荷产生层应用于以DNCA为蓝光发光材料的串联OLED器件中,获得了电流效率为8.1 cd/A的高效串联器件,比单一发光单元器件(3.2 cd/A)的效率提高了2.5倍,而启亮电压只上升了1.6倍;然后,通过调节电荷产生层中NaCl及Mg的厚度,有效地将串联器件的电流效率(21.8 cd/A)提高到6.8倍;为了验证该电荷产生层的普遍适用性,最后将最优化的NaCl/Mg/MoO_3/NPB应用到以Alq_3为发光材料的串联绿光OLED器件中,器件的电流效率仍会随着发光单元的增加得到有效地提高,同时器件的启亮电压不会成倍的提高。
[Abstract]:In recent years, the organic electroluminescent device (Ole) has made great progress in the field of display and lighting, and further improving the luminous efficiency and stability of the device is still the key problem in the process of commercialization of OLED. Compared with traditional OLED devices, OLED devices with series structure have many advantages, such as high brightness, high current efficiency and good stability, so they are favored by people from all walks of life. However, series OLED devices still have problems such as high starting voltage and high current efficiency. In this paper, we focus on how to optimize the carrier injection, transmission and balanced recombination to fabricate efficient OLED devices. On the other hand, according to the structure of the composite electronic buffer layer, we study how to optimize the carrier injection, transmission and balance recombination. Furthermore, a novel charge generation layer is designed, and a series OLED device with low starting voltage and high efficiency is fabricated. The specific research contents are as follows: firstly, the alkali metal chloride NaCl thin layer is inserted into the hole transport layer NPB, and the number of holes injected into the OLED layer is regulated by adjusting the thickness of the NaCl thin layer, which effectively improves the current efficiency of the OLED device. The maximum current efficiency of the optimized device is 5.3 CD / A, which is 29.3 higher than that of the conventional device (4.1 CD / A). Then, the TCNQ is inserted between the electron transport layer (Bphen) and the cathode as the non-doped electronic buffer layer. By optimizing the thickness of TCNQ, the transmission and injection ability of electrons are improved. In addition, TCNQ can also improve the contact characteristics between the cathode and the transmission layer, thus increasing the luminance, current efficiency and power efficiency of the device by 37.1% and 162.558% respectively. In the same way, the NaCl thin layer is combined with the metal mg as the electronic buffer layer, which effectively balances the holes and electrons injected into the luminescent layer and improves the current efficiency of the device. The maximum current efficiency of the optimized device is 6.9 CD / A, which is 68.3% higher than that of the conventional device (4.1 CD / A). Based on the NaCl/Mg buffer layer in the previous chapter, it can effectively improve the injection ability of electrons. A novel non-doped charge generation layer:: NaCl-P / mg / Moo _ 3 / NPB is constructed. Firstly, the working mechanism of the charge generation layer is explained by the fabrication of single electron transport device and single hole transmission device. The charge generation layer is applied to the series OLED device with DNCA as the blue luminescent material. A high efficiency series device with a current efficiency of 8.1 cd/A is obtained, which is 2.5 times more efficient than that of a single light-emitting unit device (3.2cd / A), and only a 1.6-fold increase in the on-off voltage. Then, by adjusting the thickness of NaCl and mg in the charge generation layer, In order to verify the universal applicability of the charge generation layer, the optimized NaCl/Mg/MoO_3/NPB is applied to the series green OLED devices with Alq_3 as the luminescent material. The current efficiency of the device will still be improved effectively with the increase of the luminescent cell, and the starting voltage of the device will not be increased exponentially.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN383.1

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