In situ coating carbon nanotubes with wurtzite ZnS nanocrystals

A new wet-chemical method to coat multiwalled carbon nanotubes (MWNTs) with wurtzite ZnS nanocrystals was developed. The method involved modification of MWNTs with polyethyleneimine or sodium dodecyl sulfate, and reflux of modified MWNTs, ZnCl2, and thiourea in ethylene glycol solution at 150 degrees C. The composites were investigated by X-ray diffraction, transmission electron microscopy, Fourier transform infrared, and UV-visible absorption spectrum. The results showed that MWNTs were coated with a layer of ZnS nanoparticles with a size of 6 nm, and their electronic structure was not destroyed after coating with ZnS. The MWNTs/ZnS composites showed a slight blue shift because of the quantum size effect.