Department of Physics and TcSUH, University of Houston , Houston, Texas 77204, United States.
Department of Materials Science & Engineering, Southern University of Science & Technology , Shenzhen, Guangdong 518055, China.
Nano Lett. 2017 Feb 8;17(2):1090-1096. doi: 10.1021/acs.nanolett.6b04613. Epub 2017 Jan 23.
Silver nanowire (AgNW) films have been studied as the most promising flexible transparent electrodes for flexible photoelectronics. The wire-wire junction resistance in the AgNW film is a critical parameter to the electrical performance, and several techniques of nanowelding or soldering have been reported to reduce the wire-wire junction resistance. However, these methods require either specific facilities, or additional materials as the "solder", and often have adverse effects to the AgNW film or substrate. In this study, we show that at the nanoscale, capillary force is a powerful driving force that can effectively cause self-limited cold welding of the wire-wire junction for AgNWs. The capillary-force-induced welding can be simply achieved by applying moisture on the AgNW film, without any technical support like the addition of materials or the use of specific facilities. The moisture-treated AgNW films exhibit a significant decrease in sheet resistance, but negligible changes in transparency. We have also demonstrated that this method is effective to heal damaged AgNW films of wearable electronics and can be conveniently performed not only indoors but also outdoors where technical support is often unavailable. The capillary-force-based method may also be useful in the welding of other metal NWs, the fabrication of nanostructures, and smart assemblies for versatile flexible optoelectronic applications.
银纳米线 (AgNW) 薄膜已被研究作为最有前途的柔性透明电极用于柔性光电应用。AgNW 薄膜中的线线结电阻是影响其电学性能的关键参数，已有几种纳米焊接或钎焊技术被报道用于降低线线结电阻。然而，这些方法要么需要特定的设备，要么需要额外的材料作为“焊料”，并且往往对 AgNW 薄膜或衬底有不利影响。在本研究中，我们表明在纳米尺度上，毛细作用力是一种强大的驱动力，可以有效地导致 AgNW 线线结的自限制冷焊。通过在 AgNW 薄膜上施加湿气，即可简单地实现毛细作用力诱导的焊接，而无需任何技术支持，如添加材料或使用特定设备。经湿气处理的 AgNW 薄膜表现出线电阻显著降低，但透明度几乎没有变化。我们还证明，这种方法对于修复可穿戴电子设备中损坏的 AgNW 薄膜非常有效，不仅可以在室内进行，而且在技术支持通常不可用的室外也可以方便地进行。基于毛细作用力的方法可能也适用于其他金属 NW 的焊接、纳米结构的制造以及用于多功能柔性光电应用的智能组件。
