Water-soluble and highly fluorescent hybrids of multi-walled carbon nanotubes with uniformly arranged gold nanoparticles

Water-soluble hybrids of multi-walled carbon nanotubes (MWNTs) and gold nanoparticles (Au@ MWNTs) were fabricated via the in situ solution method and characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS). An optoelectronic-active compound of N,N'-bi(2-mercaptoethyl)perylene-3,4,9,10-tetracarboxylic diimide (MEPTCDI) was employed as interlinker and stabilizer for the formation of the Au@MWNTs hybrids. The size of Au nanoparticles in the hybrids can be controlled and decreased to a limited small range with high stability via this in situ fabrication approach. The hybrid formation mechanism was proposed by making comparison with other hybrids, employing various organic or organic groups as interlinkers, and was further demonstrated by TEM, ultraviolet-visible (UV-vis), and atomic absorption measurements. The optical properties of the Au@MWNTs hybrids were studied, and it was found that the hybrid exhibited strong visible luminescence under UV lamp irradiation, which might extend its potential applications to biological labeling, etc.