Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, MI 48109-2122, USA.
Nanoscale. 2012 Jan 21;4(2):639-44. doi: 10.1039/c1nr11574j. Epub 2011 Dec 7.
Graphene is considered as a promising candidate to replace conventional transparent conductors due to its low opacity, high carrier mobility and flexible structure. Multi-layer graphene or stacked single layer graphenes have been investigated in the past but both have their drawbacks. The uniformity of multi-layer graphene is still questionable, and single layer graphene stacks require many transfer processes to achieve sufficiently low sheet resistance. In this work, bilayer graphene film grown with low pressure chemical vapor deposition was used as a transparent conductor for the first time. The technique was demonstrated to be highly efficient in fabricating a conductive and uniform transparent conductor compared to multi-layer or single layer graphene. Four transfers of bilayer graphene yielded a transparent conducting film with a sheet resistance of 180 Ω(□) at a transmittance of 83%. In addition, bilayer graphene films transferred onto the plastic substrate showed remarkable robustness against bending, with sheet resistance change less than 15% at 2.14% strain, a 20-fold improvement over commercial indium oxide films.
石墨烯被认为是一种很有前途的替代传统透明导体的材料，因为它的低不透明度、高载流子迁移率和灵活的结构。过去已经研究了多层石墨烯或堆叠的单层石墨烯，但它们都有缺点。多层石墨烯的均匀性仍存在疑问，而单层石墨烯堆叠需要多次转移过程才能达到足够低的方阻。在这项工作中，首次使用低压化学气相沉积生长的双层石墨烯薄膜作为透明导体。与多层或单层石墨烯相比，该技术在制备导电且均匀的透明导体方面表现出了很高的效率。经过四次双层石墨烯的转移，得到了一个透明导电薄膜，其方阻为 180 Ω(□)，透光率为 83%。此外，转移到塑料基底上的双层石墨烯薄膜具有出色的抗弯曲性，在 2.14%的应变下，方阻变化小于 15%，比商用氧化铟薄膜提高了 20 倍。
