银纳米线电极在有机电致发光器件中的应用研究

发布时间：2018-06-24 08:34

本文选题：有机电致发光器件 + 银纳米线　；参考：《吉林大学》2015年硕士论文

【摘要】：有机电致发光器件（Organic Light-Emitting Device, OLED）具有主动发光、温度相应特性好、质量轻、亮度高等优点，所以近年来引起了人们的广泛关注。OLED最突出的优点就是可以实现柔性，这使其在柔性光电领域，如电子报纸或者可穿戴产品上具有很高的应用前景。众所周知，实现柔性OLED制备中的关键之一就是柔性电极的选择。ITO是最常用的透明电极材料，因为其在可见光范围内具有很高的透过率，并且导电性很好。但是它本身性质很脆，，易断裂，成膜的过程需要高温溅射，而且随着铟储量的缺乏使得ITO的成本越来越高，这些都限制了其在柔性器件中的应用。迄今为止业界研制出了很多代替ITO作为柔性电极的材料，例如石墨烯、碳纳米管、导电聚合物、银纳米线等等。石墨烯最成熟的技术是通过CVD生长制备，但其成本很高；碳纳米管因为管与管之间的结合不好使得其方块电阻很高；导电聚合物的光电性能也一直无法达到ITO的水平。银纳米线薄膜是随机分布的网格结构，具有很好的延展性和机械稳定性，制备方法非常简单，其光电性能也可以达到ITO水平，所以银纳米线是一种很好的代替ITO的材料。但是银纳米线是不规则的网状结构，这使得直接制备在衬底上的银纳米线薄膜粗糙度很大，最高可以达到几百纳米，造成器件短路，这也是至今利用银纳米线电极制备柔性有机电致发光器件的文章鲜有发表的原因。本文首先利用脱模工艺技术，在柔性衬底上制备了银纳米线薄膜。通过原子力显微镜测试可以证明，相对于直接制备在玻璃衬底上的银纳米线薄膜，利用脱膜工艺技术可以有效地降低薄膜的表面粗糙度，粗糙度由78.3nm下降到了3.81nm。所制得的银纳米线电极的光电性能也是非常好的，在方块电阻为50Ω/sq时透过率可以达到80%，并且脱膜工艺技术不会影响薄膜的表面形貌。我们利用银纳米线电极在柔性衬底上制备了有机电致发光器件，所制得的器件具有很好的光电性能和机械稳定性。之后我们利用聚合物材料PEDOT:PSS与银纳米线结合制备了复合薄膜，并利用脱膜工艺技术将其制备在了柔性衬底上，这同样降低了复合薄膜的表面粗糙度，由27.2nm下降到了0.372nm。我们测试了复合薄膜的光电性能，与单独的两种材料所制备的薄膜相比都有显著提高。最后我们利用复合薄膜作为透明电极，在柔性衬底上制备了有机电致发光器件，其最大亮度可以达到5380cd/m2，最大效率为51.3cd/A。所得的柔性器件具有非常好的机械稳定性，在弯折50次的过程当中器件可以保持非常好的发光状态，且效率并没有发生明显改变。
[Abstract]:Organic Light-Emitting device (OLED) has the advantages of active luminescence, good temperature characteristic, light mass, high brightness and so on. This makes it have a high application prospect in flexible optoelectronic fields, such as electronic newspapers or wearable products. It is well known that the choice of flexible electrode. ITO is the most commonly used transparent electrode material in the fabrication of flexible OLED because of its high transmittance and good conductivity in the visible light range. However, its properties are brittle, easy to break, the process of film formation needs high temperature sputtering, and with the lack of indium reserves, ITO costs more and more, which limits the application of ITO in flexible devices. So far, many materials have been developed to replace ITO as flexible electrodes, such as graphene, carbon nanotubes, conductive polymers, silver nanowires and so on. The most mature technology is to prepare graphene by CVD, but its cost is very high; carbon nanotubes (CNTs) have high square resistance due to the poor bonding between tubes and tubes; and the optoelectronic properties of conductive polymers have not been able to reach the level of ITO. Silver nanowires are randomly distributed mesh structures with good ductility and mechanical stability. The preparation method is very simple and its photoelectric properties can reach ITO level. So silver nanowires are a good substitute for ITO. But the silver nanowires are irregular mesh structure, which makes the silver nanowires directly prepared on the substrate have a great roughness, up to several hundred nanometers, resulting in a short circuit of the devices. This is why there are few published articles on the fabrication of flexible organic electroluminescent devices using silver nanowire electrodes. In this paper, silver nanowire films were prepared on flexible substrates by demoulding technology. Compared with the silver nanowire films deposited directly on glass substrates, the surface roughness of the films can be effectively reduced by defilm technology from 78.3nm to 3.81nm. the atomic force microscopy (AFM) results show that the surface roughness of the films is reduced from 78.3nm to 3.81nm. The photovoltaic properties of the silver nanowire electrode are also very good. The transmittance of the silver nanowire electrode is up to 80 when the square resistance is 50 惟 / sq, and the surface morphology of the film will not be affected by the de-film technology. We have fabricated organic electroluminescent devices on flexible substrates using silver nanowire electrodes. The fabricated devices have good optoelectronic properties and mechanical stability. After that, the composite films were prepared by combining the polymer PEDOT: PSS with silver nanowires, and the composite films were prepared on flexible substrates by demembrane technology, which also reduced the surface roughness of the composite films from 27.2nm to 0.372nm. The optoelectronic properties of the composite films have been tested and compared with the films prepared by two kinds of materials. Finally, we fabricated organic electroluminescent devices on flexible substrate using composite film as transparent electrode. The maximum luminance of organic electroluminescent devices can reach 5380cd/ m2 and the maximum efficiency is 51.3cd/ A. The obtained flexible device has very good mechanical stability. It can maintain a very good luminescence state during the 50 times bending process, and the efficiency has not changed obviously.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN383.1

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