Richard B. Kaner
Distinguished Professor of Chemistry
Distinguished Professor of Materials Science & Engineering
Dr. Myung Ki Hong Endowed Chair in Materials Innovation
Univerisity of California, Los Angeles
Graphene is the ultimate two-dimensional material consisting of a single layer of sp2 hybridized carbon. Here we explore different approaches to synthesize this carbon allotrope, ranging from chemical conversion to vapor phase deposition. Briefly, graphite can be converted into graphene oxide (GO) sheets, which readily disperse in water, and then can be reduced by various methods.1-2 Due to its unique ability to be solution processed and patterned, GO and chemically converted graphene hold promise for applications ranging from sensors to transparent conducting electrodes.3-4 Chemical vapor deposition onto metal substrates enables the growth of continuous, large-area graphene (Fig. 1). The challenges of growing graphene, controlling the number of layers, transferring graphene and some exciting uses such as laser scribed graphene for supercapacitors will be discussed.5-6
Fig. Large-area single layer graphene transferred onto a silicon substrate with a 300 nm oxide can be seen with the naked eye, while STM imaging enables seeing the honeycomb network of carbon that makes this material so robust.
References: 1. D. Li, M.B. Muller, S. Gilje, R.B. Kaner and G.G. Wallace, “Processable aqueous dispersions of graphene nanosheets”, Nature Nanotechnology 3, 101-105 (2008).
2. M.F. El-Kady, V. Strong, S. Dubin and R.B. Kaner, “Laser printing of flexible graphene-based supercapacitors with ultrahigh power and energy densities”, Science 335, 1326-1330 (2012).
3. J.Wassei, R.Kaner, “Oh the places you’ll go with graphene”, Acc. Chem. Res., 46, 2244-2251 (2013).
4. M.F. El-Kady, M. Ihns, M. Li, J.Y. Hwang, M.F. Mousavi, L. Chaney, A.T. Lech and R.B. Kaner, “Engineering three-dimensional hybrid supercapacitors and microsupercapacitors for high-performance integrated energy storage”, Proc. Nat. Acad. Sci., 112, 4233-4238 (2015).
5. M.F. El-Kady, Y. Shao, R.B. Kaner, “Graphene for batteries, supercapacitors and beyond”, Nature Review Materials, 1, 16033-16046 (2016).
6. Y. Shao, M.F. El-Kady, J. Sun, Y. Li, Q. Zhang, M. Zhu, H. Wang, B. Dunn and R.B. Kaner, “Design and mechanisms of asymmetric supercapacitors”, Chem. Rev., 118, 9233-9280 (2018).