Shun Mao, Ganhua Lu and Junhong Chen1
Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee,
WI 53211, USA
Received 4 July 2008, in final form 30 August 2008
Published 9 October 2008
Online at stacks.iop.org/Nano/19/455610
A simple method that combines an electrospray technique with directed assembly using an electrostatic field was used for decorating carbon nanotubes (CNTs) with nanocrystals. Colloidal CdSe and Au nanocrystals were electrosprayed and assembled onto random CNTs and vertically aligned CNTs in a controlled manner. The high level of electrical charge on the electrosprayed aerosol nanocrystals was responsible for the assembly. The technique can be used to assemble various compositions of nanomaterials onto different substrates and provides a versatile route for producing novel hybrid nanostructures.
Figure 1. Schematic of the nanocrystal aerosolization by an electrospray process and the subsequent assembly of nanocrystals onto random CNTs or vertically aligned CNTs by ESFDA (Electrostaic Force Directed Assembly).
In summary, an electrospray process was combined with an ESFDA process to coat CNTs with nanocrystals produced in the solution. Colloidal CdSe and Au nanocrystals were successfully electrosprayed and assembled onto random CNTs and CNT array in a controlled manner. No agglomeration of the nanocrystals was found after the assembly. The surface charge of electrosprayed aerosol was responsible for the successful assembly. This simple technique could be extended to other colloidal nanocrystals that are readily available, with proper adjustments of the nanocrystal concentration and the solution conductivity. The resulting novel hybrid nanostructures are expected to provide tremendous opportunities for exploring nanoscience, nanotechnology, and biotechnology.