Department of Chemical Engineering , Monash University , Clayton , Victoria 3800 , Australia.
The Melbourne Centre for Nanofabrication , 151 Wellington Road , Clayton , Victoria 3800 , Australia.
Nano Lett. 2018 Jun 13;18(6):3593-3599. doi: 10.1021/acs.nanolett.8b00694. Epub 2018 May 16.
Percolation networks of one-dimensional (1D) building blocks (e.g., metallic nanowires or carbon nanotubes) represent the mainstream strategy to fabricate stretchable conductors. One of the inherent limitations is the control over junction resistance between 1D building blocks in natural and strained states of conductors. Herein, we report highly stretchable transparent strain-insensitive conductors using fractal gold (F-Au) nanoframework based on a one-pot templateless wet chemistry synthesis method. The monolayered F-Au nanoframework (∼20 nm in thickness) can be obtained from the one-pot synthesis without any purification steps involved and can be transferred directly to arbitrary substrates like polyethylene terephthalate, food-wrap, polydimethylsiloxane (PDMS), and ecoflex. The F-Au thin film with no capping agents leads to a highly conductive thin film without any post-treatment and can be stretched up to 110% strain without significantly losing conductivity yet with the optical transparency of 70% at 550 nm. Remarkably, the F-Au thin film shows the strain-insensitive behavior up to 20% stretching strain. This originates from the unique fractal nanomesh-like structure which can absorb external mechanical forces, thus maintaining electron pathways throughout the nanoframework. In addition, a semitransparent bilayered F-Au film on 100% prestrained PDMS could achieve to a high stretchability of 420% strain with negligible resistance changes under low-level strains.
一维（1D）构建块（例如金属纳米线或碳纳米管）的渗滤网络是制造可拉伸导体的主流策略。其中一个固有局限性是控制 1D 构建块在导体的自然和应变状态下的结电阻。在此，我们报告了使用基于一锅无模板湿化学合成方法的分形金（F-Au）纳米框架的高拉伸透明应变不敏感导体。单层 F-Au 纳米框架（厚度约为 20nm）可以从一锅合成中获得，而无需涉及任何纯化步骤，并且可以直接转移到任意基底上，如聚对苯二甲酸乙二醇酯、食品包装、聚二甲基硅氧烷（PDMS）和 ecoflex。没有封端剂的 F-Au 薄膜导致无需后处理即可获得高导电性的薄膜，并且可以拉伸至 110%的应变而不会显著失去导电性，同时在 550nm 处保持 70%的光学透明度。值得注意的是，F-Au 薄膜在高达 20%的拉伸应变下表现出应变不敏感行为。这源于独特的分形纳米网状结构，它可以吸收外部机械力，从而在整个纳米框架中保持电子通路。此外，在 100%预拉伸 PDMS 上的半透明双层 F-Au 薄膜可以在低应变下实现 420%应变的高拉伸性，电阻变化可忽略不计。
