Electrostatic interaction of multi-walled carbon nanotubes composites with CdTe and CdSe nanoparticles

Composites were prepared by the electrostatic interaction between carboxylated multi-walled carbon nanotubes (c-MWNTs) and either cadmium telluride (CdTe) or cadmium selenide (CdSe) nanoparticles. Multi-walled carbon nanotubes (MWNTs) were oxidized by an aqueous acid mixture, and both the CdTe and CdSe nanoparticles were stabilized by 2-(dimethylamino) ethanethiol hydrochloride in water to develop negatively and positively charged outer surfaces, respectively. Optical properties were investigated by UV/Vis and photoluminescence (PL) analyses. CdX (X = Te, or Se) nanoparticles showed emissions at the same position regardless of the existence of c-MWNTs. This result suggests that the interaction between CdX and c-MWNTs does not affect the photoluminescence of CdX nanoparticles in their composites. The binding energies and redox potential positions of the CdX nanoparticles in their c-MWNT-CdX composites shifted from those of the pure nanoparticles. These changes indicate that the electron densities on the interfaces of CdX nanoparticles and c-MWNTs were redistributed after the formation of composites due to the strong electrostatic interaction between the components.