The 236th MANA and the 103rd ICYS Joint Seminar
Dr. Jung-Sub Wi & Dr. Sharali Malik
| Date | December 2, Friday |
| Time | 15:30-16:45 |
| Place | Seminar room #431, 4F, MANA Bldg., NAMIKI Site, NIMS |
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15:30-16:00
Physical Synthesis of Plasmonic Nanoparticles with Engineered Internal Sub-structures
Direct-fabrication of synthetic nanoparticles by top-down physical routes, in which materials are vacuum deposited in a nano-patterned polymer template, enables exquisite control over material composition, multilayer structure, and particle size/shape which are hardly achievable from chemical synthesis of nanoparticles. This wide freedom of nanoparticle synthesis allows us to make artificially designed nanoparticles with unique physical properties and internal sub-structures.
In this talk, several examples of physically synthesized nanoparticles (Sombrero-shaped Ag nanoparticle[1], Two-tiered Ag nanoparticle with a concentric cavity[2], Three-tiered Au nanodisk for broadband light harvesting[3] will be introduced with detailed discussions on the synthesis method and nanoparticle properties.
References
- [1]J. -S. Wi, et al., ACS Nano 5, 6449 (2011).
- [2]J. -S. Wi, et al., Small, published online, DOI:10.1002/20110152 (2011).
- [3]J. -S. Wi, et al., manuscript in preparation.
Speaker
Dr. Jung-Sub Wi, ICYS-MANA Reseacrher, NIMS
Chair
Dr. Tadaaki Nagao, MANA Scientist, NIMS
16:00-16:45
Characterization of Graphene Nanosheets: from Graphite to GO/RGO
Graphene is the ideal candidates in advanced applications as electronics[1][2], hydrogen storage[3] and nano-biotechnology[4]. This great interest is motivated by their exceptional physical properties such as high charge carrier mobility up to 1,000,000 cm2/Vs[5-7]. Single layer graphene sheet was first obtained by mechanical exfoliation of graphite platelets[7]. However, this method is not suitable for large scale production of graphene. Therefore, solution routes consisting of exfoliation of graphite by solvents and the stabilization of the exfoliated graphene in suspension have been investigated as an alternative method to produce graphene. However, it is well known that the quality and properties of graphene oxide (GO) and reduced graphene oxide (RGO) depends on fabrication conditions and that the process is still not fully understood. In this work we aim to get a better understanding of some aspects of this process.
In this talk we describe the characterization of graphene oxide (GO) at various stages in the oxidation process from graphite to graphene oxide and the reduced graphene oxide (RGO) made from the GO at each stage in order to find the best conditions for making GO and RGO. Good quality GO is required in many novel battery systems and good quality RGO is required for high performance composite materials.
References
- [1] Z. F. Wang et al., ACM J Emerg Technol Comput Syst 5 (2009).
- [2] G. Eda et al., Nat Nanotechnol 3, 270 (2008).
- [3] D.C. Elias et al., Science 323, 610 (2009).
- [4] N. Chopra et al., Chem Mater 21, 1176 (2009).
- [5] K. I. Bolotin et al., Solid State Commun 146, 351 (2008).
- [6] J. R. Williams et al., Science 317, 638 (2007).
- [7] A. K. Geim et al., Nature 306, 666 (2004).
Speaker
Dr. Sharali Malik, The Institute of Nanotechnology, Karlsruhe Institute of Technology, Germany
Chair
Dr. Jonathan Hill, MANA Scientist, NIMS