The outstanding electrical, mechanical and chemical properties of graphene make it attractive for applications in flexible electronics. However, efforts to make transparent conducting films from graphene have been hampered by the lack of efficient methods for the synthesis, transfer and doping of graphene at the scale and quality required for applications. Here, we report the roll-to-roll production and wet-chemical doping of predominantly monolayer 30-inch graphene films grown by chemical vapour deposition onto flexible copper substrates. The films have sheet resistances as low as μ125ω-1 with 97.4% optical transmittance, and exhibit the half-integer quantum Hall effect, indicating their high quality. We further use layer-by-layer stacking to fabricate a doped four-layer film and measure its sheet resistance at values as low as μ30ω ω-1 at μ90% transparency, which is superior to commercial transparent electrodes such as indium tin oxides. Graphene electrodes were incorporated into a fully functional touch-screen panel device capable of withstanding high strain.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (2009-0081966, 2009-0082608, 2009-0083540, 2009-0090017, World Class University R33-2008-000-10138-0, National Honor Scientist Program), the Research Centre of Breakthrough Technology Program through the Korea Institute of Energy Technology Evaluation and Planning (KETEP), funded by the Ministry of Knowledge Economy (2009-3021010030-11-1), Singapore National Research Foundation (NRF-RF2008-07) & NUS NanoCore, and T.J. Park Junior Faculty Fellowship. The authors thank R. Ruoff (University of Texas at Austin) and P. Kim (Columbia University) for helpful comments, W.S. Lim, K.D. Kim and Y.D. Kim (SKKU) for assistance in XPS analysis, and Samkwang Well Tech Co. for assistance with the touch-panel fabrication.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Biomedical Engineering
- Materials Science(all)
- Condensed Matter Physics
- Electrical and Electronic Engineering