兰州大学机构库 >物理科学与技术学院
三维衬底表面银纳米线基透明导电薄膜的制备与性能研究
Alternative TitleFabrication and properties of AgNWs-based transparent conductive films on 3D substrates
杨志伟
Thesis Advisor兰伟
2017-06-01
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword三维结构化表面衬底 透明导电薄膜 纳米线网络薄膜 透光率 方块电阻 柔韧性 弹性
Abstract

当前,透明导电薄膜在实际工业生产中扮演着非常重要的角色,它广泛应用于触摸板,液晶显示器,太阳能电池,有机发光二极管等光电器件上。商用透明导电薄膜材料是铟锡氧化物(ITO),其具有良好的透光和导电性能。然而,铟属于稀有金属,同时ITO作为一种陶瓷材料具有天然的结构脆性,这局限了ITO在未来柔性光电子器件中的应用。所以,选择新材料取代ITO就显得非常迫切。ITO的潜在替代材料包括碳纳米管、石墨烯、导电聚合物以及金属纳米线等,其中金属纳米线以光电性能和柔性优异成为最佳候选材料之一。在金属纳米线网络薄膜中,以银纳米线(AgNWs)的材料工艺最为成熟,因为银纳米线网络薄膜具有非常优异的透光导电性能同时具备良好的机械柔韧性。因此具有取代ITO材料的应用潜力。

光电子器件为了增强光利用率提高性能,器件表面逐渐由二维平面向三维结构化设计发展,例如硅纳米线阵列太阳能电池、硅基径向微米柱阵列太阳能电池、InGaAs基纳米线太阳能电池、核壳阵列光探测器等。透明导电薄膜是光电子器件中非常重要的组成部分,为了完全适应新结构器件的要求,有必要开展三维衬底上透明导电薄膜的制备与性能研究。应用新型透明导电薄膜后,可进一步改善光电子器件的性能,例如,在三维表面太阳能电池上引入三维结构的透明导电薄膜能够更充分的收集载流子,改善电池光电转化效率。本论文就如何制备出高性能三维衬底表面银纳米线基透明导电薄膜进行了两部分研究工作。

第一,通过三步骤在三维非常规衬底表面制备得到了银纳米线基透明导电薄膜:首先,在透明玻璃、PET衬底上利用玻璃刀或刀片进行划痕处理,获得三维结构化表面衬底;接着,以AgNWs分散液为原料,在三维衬底上旋涂沉积AgNWs网络薄膜,之后再旋涂一层ZnO前驱物保护层,防止AgNWs在空气中氧化,同时增强AgNWs在衬底上的粘附力;最后,在惰性气体气氛中对AgNWs网络薄膜进行热处理,利用热焊接降低AgNWs之间的接触电阻,同时让ZnO前驱物分解生成均匀的ZnO薄膜,提高AgNWs网络薄膜的透光导电性能以及稳定性。在三维衬底上制备得到的AgNWs/ZnO透明导电薄膜获得了88 %的可见光透光率和10 Ω/□左右的方块电阻,将该薄膜在80 oC高温环境下连续放置一个月以上,薄膜性能不发生衰减。为了验证薄膜的粘附性,对三维衬底上的AgNWs/ZnO薄膜进行透明胶带粘贴十次以上,发现薄膜完好无损,性能几乎不受影响。对PET柔性基底上的AgNWs/ZnO透明导电薄膜进行了柔韧性测试,发现弯曲千次以上薄膜电阻几乎没有变化,说明该透明电极的弯曲柔韧性非常好。因此,通过我们的技术工艺获得的三维衬底表面上AgNWs/ZnO透明导电薄膜,在透光、导电、稳定性和柔韧性方面,完全可以与传统二维ITO透明导电薄膜性能相匹配,甚至更优。

第二,上述实验中,由于三维衬底表面结构不规则且不具备弹性,所以接下来我们选择用光刻工艺制备三维规则结构化表面衬底,然后通过PDMS转移得到三维衬底表面银纳米线弹性透明导电薄膜。制备工艺过程如下:首先,使用SU8光刻胶,通过光刻工艺在Si衬底上制备出不同尺寸不同规则结构的三维衬底,包括条、圆柱和方柱;然后在上面旋涂AgNWs分散液,获得三维衬底表面AgNWs网络薄膜;最后将PDMS滴涂在沉积了AgNWs网络薄膜的三维衬底上,固化后剥离形成的三维衬底AgNWs/PDMS弹性透明导电薄膜。通过SEM分析发现AgNWs在不同尺寸和不同形貌的三维结构衬底上可以均匀分布,特别是在棱角等特殊区域都能均匀分布。所得透明导电薄膜透光率为90 %、方块电阻为26 Ω/□。在柔韧性测试方面,将三维衬底AgNWs/PDMS弹性透明导电薄膜在5 mm曲率半径下弯曲千次以上,在1 mm曲率半径以下,薄膜电阻都依然保持不变,而且拉伸30 %以内电阻基本保持不变。当拉伸到100 %后,电阻从26 Ω/□增加到38.5 Ω/□,仅增加不到50 %。对其进行拉伸的疲劳韧性的测试中,30 %以内的往返拉伸进行百次后,电阻增加不超过12 %,说明AgNWs/PDMS弹性透明导电薄膜具有高柔韧性和抗拉伸疲劳能力。该技术可对未来三维结构化表面弹性光电子器件的应用提供技术支持。

Other Abstract

At present, transparent conductive films (TCFs) play an important role in some fields, such as touch panels, liquid crystal displays, solar cells, organic light emitting diodes. The main commercial materials of TCFs is indium tin oxide (ITO), due to its low electrical resistance and high transparency. However, the disadvantages, such as the rare metal of indium and the brittleness, limit the applications of ITO in flexible optoelectronic devices. Alternative materials to ITO, such as conducting polymers, carbon nanotubes, graphene, metal nanowires exhibit greatly improved flexibility. Wherein, silver nanowires (AgNWs)-based TCFs show excellent optical transmittance, electrical conduction and good flexibility. So, AgNWs are the most promising materials to replace ITO.

To increase light utilization and improve performance, the surface of optoelectronic devices is developed 3D structured surface, such as solar cells of silicon nanowire arrays, silicon based solar cells with radial microcolumn arrays, InGaAs-based nanowire solar cells, core-shell array photodetectors. TCFs are a very important component in optoelectronic devices. To fully meet the requirements in new structural optoelectronic devices, it is necessary to study the novel TCFs on the substrates with 3D structured surface. In this paper, the study focused on preparation and properties of high performance AgNWs-based TCFs on various 3D substrates, including the treated 3D glass, poly ethylene terephthalate (PET) and polydimethylsiloxane (PDMS).

1, The novel AgNWs/ZnO TCFs were prepared on the treated glass and PET substrates with 3D structured surface. The glass and PET substrates were scratched by glass cutter or doctor blade to get 3D structured surface. AgNWs network films were deposited on the treated 3D substrates, and then thin ZnO layer was employed to protect AgNWs from oxidation in air. The AgNWs/ZnO films showed the superior performances with the optical transmittance of ~88 %, and the sheet resistance of ~10 Ω/sq. The films maintained the thermal stability of more than 1 month at 80 oC. In order to verify the adhesion of the TCFs, the AgNWs/ZnO films was pasted with scotch tape for more than ten times, the performances were almost unaffected. Flexibility testing of AgNWs/ZnO TCFs on the treated PET flexible substrate was carried out, it was found that there was little change in sheet resistance above 1000 times bending, which indicated that the films had a very good flexibility. Therefore, the high-performance AgNWs/ZnO TCFs on the 3D unconventional substrates were achieved, which can be comparable to conventional ITO films.

2, Based on the above experiments, the stretchable AgNWs TCFs on the PDMS substrates with different 3D regular structured surfaces were fabricated by photolithography. The preparation procedure was as follows. SU8 photoresist was used. Different 3D structures were fabricated on Si substrate by photolithography including bars, columns, and square columns. AgNWs dispersion was spin-coated on the 3D structures to get AgNWs network films. The PDMS were drop-coated on 3D structures with AgNWs network films. After curing, 3D AgNWs/PDMS stretchable TCFs were formed after peeling off. The results showed that AgNWs can be uniformly distributed in the surface of 3D PDMS structures with different sizes and morphologies, especially in the corners, the walls and the other special regions. The transmittance of the AgNWs/PDMS TCFs was 90 %, and the sheet resistance was 26 Ω/□. The sheet resistance remained constant under various harsh conditions, including bending 1000 times at 5 mm curvature radius, bending at 1mm curvature radius, and 30 % stretch. Under the 50 % stretch, the sheet resistance increased from 26 Ω/□ to 38.5 Ω/□. In the stretch fatigue test, the sheet resistance of the TCFs increased ≤ 12 %. The technique can provide a technical support for the applications of stretchable optoelectronic devices with 3D structured surface.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229427
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
杨志伟. 三维衬底表面银纳米线基透明导电薄膜的制备与性能研究[D]. 兰州. 兰州大学,2017.
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