具有嵌入式金属网的高性能，灵活，透明电极的可扩展解决方案处理制造策略
1Department of Mechanical Engineering,University of Hong Kong, 2Department of Mechanical Engineering,University of Michigan, 3Department of Electrical Engineering and Computer Science,University of Michigan, 4Department of Chemistry,University of Hong Kong, 5HKU-Shenzhen Institute of Research and Innovation
Summary
该协议描述了一种基于解决方案的制造策略，用于高性能，灵活，透明的电极，具有完全嵌入的厚金属网。通过该方法制造的柔性透明电极表现出最高的报告性能，包括超低薄层电阻，高光透射率，弯曲下的机械稳定性，强的基板粘附性，表面光滑度和环境稳定性。
Abstract
在这里，作者报道了嵌入式金属网状透明电极（EMTE），一种新的透明电极（TE），其中金属网完全嵌入聚合物膜中。本文还为这种新型TE提出了一种低成本，无真空制造方法;该方法结合光刻，电镀和压印传输（LEIT）处理。 EMTE的嵌入性提供了许多优点，如高表面平滑度，这对于有机电子器件生产至关重要;弯曲时机械稳定性好;耐化学品和耐湿性良好;并与塑料薄膜粘附力强。 LEIT制造具有无电镀金属沉积的电镀工艺，有利于工业批量生产。此外，LEIT允许制造具有高纵横比（ 即，厚度至线宽）的金属网，显着增强其导电性而不会不利地丢失光学transmittance。我们展示了几种灵活的EMTE原型，薄片电阻低于1Ω/ sq，透光率大于90％，导致非常高的品质因数（FoM） – 高达1.5 x 10 4 – 这是最佳值出版文献
Introduction
在全球范围内，正在进行研究以寻找刚性透明导电氧化物（TCO）的替代物，例如氧化铟锡和氟掺杂氧化锡（FTO）膜，以便制造柔性/可拉伸的TE用于将来的柔性/可伸缩光电器件1 。这需要新的材料与新的制造方法。
已经研究了诸如石墨烯2 ，导电聚合物3,4 ，碳纳米管5和随机金属纳米线网络6,7,8,9,10,11等纳米材料，并已经证明了它们在柔性TE中的能力，解决了现有的基于TCO的TE，包括薄弱12 ，低红外透射13 ，低丰度14 。即使有这种潜力，在连续弯曲下也不会发生恶化，仍然难以获得高的电和光电导率。
在这种框架下，正常金属网15,16,17,18,19,20正在发展成为有望的候选者，并且已经实现了非常高的光学透明度和低的薄层电阻，这是可以根据需要调整的。然而，由于众多挑战，广泛使用金属网状TE已经受到阻碍。首先，制造通常涉及昂贵的真空沉积金属16,17 ， </sup> 18，21 。第二，薄膜有机光电器件的厚度可能容易导致电气短路22,23,24,25 。第三，与基材表面的弱粘合导致柔性差26,27 。上述限制已经引起了对基于金属网的新型结构和其制造的可扩展方法的需求。
在本研究中，我们报告了一种新颖的柔性TE结构，其中包含完全嵌入聚合物膜的金属网。我们还描述了一种创新的，基于解决方案的低成本制造方法，其结合光刻，电沉积和印迹转印。样品EMTE已经实现了高达15k的FoM值。由于嵌入式的性质观察到EMTE显着的化学，机械和环境稳定性。此外，在这项工作中建立的解决方案处理的制造技术可以潜在地用于所提出的EMTE的低成本和高产量生产。这种制造技术可扩展到更精细的金属网线宽度，更大面积和一系列金属。
Protocol
注意：请注意电子束的安全。请戴上正确的防护眼镜和衣服。另外，请仔细处理所有易燃溶剂和溶液。 1.基于光刻的EMTE制造 光刻用于制造网格图案。 使用棉签将液体洗涤剂清洁FTO玻璃基板（3厘米×3厘米）。用干净的棉签将去离子水（DI）水彻底冲洗干净。使用超声波（频率= 40 kHz，温度= 25°C）在异丙醇（IPA）中进行30秒清洗，然后用压缩空气干燥?…
Representative Results
图1显示了EMTE样品的原理图和制造流程图。 如图1a所示 ，EMTE由完全嵌入聚合物膜中的金属网组成。网格的上表面与基底处于同一水平面上，显示出一般平滑的平台，用于随后的装置生产。制造技术在图1b – e中示意性地解释。在FTO玻璃基板上涂覆光致抗蚀剂膜之后，使用光刻技术通过UV曝光和?…
Discussion
我们的制造方法可以进一步修改，以允许样品的特征尺寸和面积的可扩展性以及各种材料的使用。使用EBL成功制造亚微米线宽（ 图3a-3c ）的铜质EMTE证明了LETE制造中的EMTE结构和关键步骤，包括电镀和压印传输，可以可靠地缩小到亚微米范围。类似地，也可以使用其他大面积光刻工艺，例如相移光刻30 ，纳米压印光刻31和带电粒子束光刻…
Declarações
The authors have nothing to disclose.
Acknowledgements
这项工作得到了香港特别行政区研究资助委员会（第17246116号）综合研究基金，中国国家自然科学基金（61306123）青年学者计划，基础研究计划 – 深圳市科技创新委员会通用计划（JCYJ20140903112959959），浙江省科技厅重点研究发展计划（2017C01058）。作者感谢Y.-T.黄和SP峰对光学测量的帮助。
Materials
| Acetone | Sigma-Aldrich | W332615 | Highly flammable |
| Isopropanol | Sigma-Aldrich | 190764 | Highly flammable |
| FTO Glass Substrates | South China Xiang S&T, China | ||
| Photoresist | Clariant, Switzerland | 54611L11 | AZ 1500 Positive tone resist (20cP) |
| UV Mask Aligner | Chinese Academy of Sciences, China | URE-2000/35 | |
| Photoresist Developer | Clariant, Switzerland | 184411 | AZ 300 MIF Developer |
| Cu, Ag, Au, Ni, and Zn Electroplating solutions | Caswell, USA | Ready to use solutions (PLUG N' PLATE) | |
| Keithley 2400 SourceMeter | Keithley, USA | 41J2103 | |
| COC Plastic Films | TOPAS, Germany | F13-19-1 | Grade 8007 (Glass transition temperature: 78 °C) |
| Hydraulic Press | Specac Ltd., UK | GS15011 | With low tonnage kit ( 0-1 ton guage) |
| Temperature Controller | Specac Ltd., UK | GS15515 | Water cooled heated platens and controller |
| Chiller | Grant Instruments, UK | T100-ST5 | |
| Polymethyl Methacrylate (PMMA) | Sigma-Aldrich | 200336 | |
| Anisole | Sigma-Aldrich | 96109 | Highly flammable |
| EBL Setup | Philips, Netherlands | FEI XL30 | Scanning electron microscope equipped with a JC Nabity pattern generator |
| Isopropyl Ketone | Sigma-Aldrich | 108-10-1 | |
| Silver Paste | Ted Pella, Inc, USA | 16031 | |
| UV–Vis Spectrometer | Perkin Elmer, USA | L950 |
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Citar este artigo
Khan, A., Lee, S., Jang, T., Xiong, Z., Zhang, C., Tang, J., Guo, L. J., Li, W. Scalable Solution-processed Fabrication Strategy for High-performance, Flexible, Transparent Electrodes with Embedded Metal Mesh. J. Vis. Exp. (124), e56019, doi:10.3791/56019 (2017).