ICFO-Institut de Ciencies Fotoniques , Mediterranean Technology Park, Castelldefels, Barcelona 08860, Spain.
ACS Appl Mater Interfaces. 2013 Nov 27;5(22):11756-61. doi: 10.1021/am403440n. Epub 2013 Nov 13.
Polycrystalline graphene and metallic nanowires (NWs) have been proposed to replace indium tin oxide (ITO), the most widely used transparent electrode (TE) film on the market. However, the trade-off between optical transparency (Topt) and electrical sheet resistance (Rs) of these materials taken alone makes them difficult to compete with ITO. In this paper, we show that, by hot-press transfer of graphene monolayer on Ag NWs, the resulting combined structure benefits from the synergy of the two materials, giving a Topt-Rs trade-off better than that expected by simply adding the single material contributions Ag NWs bridge any interruption in transferred graphene, while graphene lowers the contact resistance among neighboring NWs and provides local conductivity in the uncovered regions in-between NWs. The hot-pressing not only allows graphene transfer but also compacts the NWs joints, thus reducing contact resistance. The dependence on the initial NW concentration of the effects produced by the hot press process on its own and the graphene transfer using hot press was investigated and indicates that a low concentration is more suitable for the proposed geometry. A TE film with Topt of 90% and Rs of 14 Ω/sq is demonstrated, also on a flexible glass substrate about 140 μm thick, a very attractive platform for efficient flexible electronic and photonic devices.
多晶石墨烯和金属纳米线 (NWs) 已被提议替代市场上应用最广泛的透明电极 (TE) 薄膜铟锡氧化物 (ITO)。然而,这些材料的光学透明度 (Topt) 和电面电阻 (Rs) 之间的权衡,使得它们很难与 ITO 竞争。在本文中,我们表明,通过在 Ag NWs 上热压转移单层石墨烯,所得的组合结构得益于两种材料的协同作用,提供了优于简单添加单一材料贡献的 Topt-Rs 权衡关系。Ag NWs 桥接了转移石墨烯中的任何中断,而石墨烯降低了相邻 NWs 之间的接触电阻,并在 NWs 之间的未覆盖区域提供局部导电性。热压不仅允许石墨烯转移,还可以压缩 NWs 的连接,从而降低接触电阻。研究了热压过程本身以及使用热压进行石墨烯转移对初始 NW 浓度的依赖性,结果表明低浓度更适合所提出的结构。在厚度约为 140 μm 的柔性玻璃衬底上,展示了一种 Topt 为 90%、Rs 为 14 Ω/sq 的 TE 薄膜,这对于高效的柔性电子和光子器件来说是一个非常有吸引力的平台。