Tuesday, October 21, 2008

J.H.Chen

Multifunctional Hybrid Nanocrystal-Carbon Nanotube Structures

Junhong Chen*

Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI 53211
* jhchen@uwm.edu

Hybrid nanomaterials composed of nanocrystals distributing on the surfaces of carbon nanotubes (CNTs) represent a new class of materials. These materials could potentially display not only the unique properties of nanocrystals and those of CNTs, but also additional novel properties due to the interaction (e.g., electronic or optical) between the nanocrystal and the CNT. Such hybrid nanocrystal-CNT structures are promising for various innovative nanotechnological applications, including chemical sensors [1], biosensors [2], nanoelectronics [3], photovoltaic cells [4], fuel cells [5], and hydrogen storage [6]. In this talk, I will present a material-independent, dry route based on the electrostatic force directed assembly (ESFDA) to assemble aerosol nanocrystals onto CNTs [7-11]. The method takes advantage of the small diameter of CNTs for a significantly enhanced electric field near the CNT surface, which is then used to attract charged aerosol nanocrystals [12] onto oppositely-biased CNTs. The ESFDA technique works for both random CNTs and aligned CNTs without the need for chemical functionalization or other pretreatments of CNTs. There is an intrinsic nanocrystal size selection during the assembly process, which results in a narrower size distribution for nanocrystals on CNTs than that for as-produced nanocrystals. Moreover, the areal density and the actual size distribution of nanocrystals on the CNT can be controlled. The non-covalent attachment of nanocrystals also preserves the intrinsic properties of CNTs [13]. The new method enables in-situ coating of nanotubes with nanocrystals. Due to the inherent material-independence nature of the electrostatic force, various compositions of such nanocrystal-CNT hybrid structures can be produced using this new technique.


Video Content Length
36:54 Copyright: © 2008 Chen et al

References

    3. Hu, J.T., O.Y. Min, P.D. Yang, and C.M. Lieber, Controlled growth and electrical properties of heterojunctions of carbon nanotubes and silicon nanowires. Nature, 1999. 399(6731): p. 48-51.

    5. Robel, I., G. Girishkumar, B.A. Bunker, P.V. Kamat, and K. Vinodgopal, Structural changes and catalytic activity of platinum nanoparticles supported on C-60 and carbon nanotube films during the operation of direct methanol fuel cells. Applied Physics Letters, 2006. 88(7): p. 073113.

    8. Lu, G.H., L.Y. Zhu, P.X. Wang, J.H. Chen, D.A. Dikin, R.S. Ruoff, Y. Yu, and Z.F. Ren, Electrostatic-Force-Directed Assembly of Ag Nanocrystals onto Vertically Aligned Carbon Nanotubes. J. Phys. Chem. C, 2007. 111(48): p. 17919-17922.

    13. Zhu, L.Y., G.H. Lu, S. Mao, J.H. Chen, D.A. Dikin, X.Q. Chen, and R.S. Ruoff, Ripening of Silver Nanoparticles on Carbon Nanotubes. NANO, 2007. 2(3): p. 149-156.

Citation:
J.H.Chen, OAtube Nanotechnology 1, 1007 (2008). http://www.oatube.org/2008/10/jhchen.html
blog comments powered by Disqus