posted 20 Jul 2011, 03:19 by Peter Bøggild
Department of Engineering, University of Cambridge, Cambridge CB3 0FA, UK
The introduction of new, low cost nanomaterials, including graphene, Single Wall Nanotubes (SWNTs) and nanodiamonds, is set to have a disruptive impact on current products based on conventional materials, not only because of cost/performance advantages, but also because they can be manufactured in more flexible ways, suitable for a growing range of applications. In particular, the ability to manipulate the structure and composition of these carbon nanomaterials opens huge opportunities to create new products and devices with superior performance. Here I will review the main approaches to solution process carbon nanomaterials. I will first discuss how to achieve chirality-controlled SWNT dispersions [1,2] via Density Gradient Ultracentrifugation (DGU). I will then show how this technique can be extended to graphite processing  to produce graphene flakes of controlled number of layers and dimensions. A fracture mechanics model is presented to explain the exfoliation process via sonication, in order to optimise it and produces flakes with controlled dimensions[5,6]. I will show how DGU can also be used for sorting nanodiamonds in terms of shape and dimensions. These approaches for nanocarbons processing are general, and can be applied to all layered materials, such as Boron Nitride, Tungsten Disulfide, Molybdenum Disulfide. The nanocarbon dispersions produced using the above mentioned approaches, are used to fabricate composites and thin films for application in photonics and optoelectronics . In particular, I will discuss the application of nanotube and graphene composites and films in fully flexible transparent conductors, liquid crystal based smart windows, dye sensitized solar cells , and ultrafast lasers[9,10,11].
1. F. Bonaccorso, et al. J. Phys. Chem. C, 114, 17267, (2010).
2. M.C. Arnold et al. Nature Nanotech.1, 60, (2006)
3. Y. Hernandez, et al. Nature Nanotech. 3, 563 (2008).
4. A. A. Green, M. C. Hersam, Nano Lett. 9, 4031, (2009).
5. O. M. Maragò, et al. ACS Nano 4, 7515, (2010)
6. T. Hasan, et al. Physica Status Solidi B, 247, 2953, (2010).
7. J.N. Coleman et al. Science 331, 568, (2011).
8. F. Bonaccorso, et al. Nature Photon. 4, 611, (2010).
9. T. Hasan, et al. Advanced Materials 21, 3874, (2009).
10. Z. Sun, et al. ACS Nano, 4, 803 (2010). 11. F. Wang, et al. Nature Nanotech.3, 738, (2008).
Francesco Bonaccorso gained a PhD from the Department of Physics, University of Messina in Italy after working at the Italian National Research Council, the Engineering Department of Cambridge University (UK) and the Department of Physics and Astronomy of Vanderbilt University (USA). In June 2009 he was awarded a Royal Society Newton International Fellowship at the Engineering Department of Cambridge University, and elected to a Research Fellowship at Hughes Hall, Cambridge. He is currently Honorary Research Convenor at Hughes Hall and research associate at the nanomaterials spectroscopy group (NMS) in the Department of Engineering, Cambridge University. His research interests encompass solution processing of carbon nanomaterials (such as graphene, nanotubes and nanodiamonds), their spectroscopic characterization, incorporation into polymer composites and application in solar cells, light emitting devices, smart windows and touch-screens.