A facile synthetic approach and optical properties of AuNPs/CdSe tetrapod and AuNPs/CdSe@rGO nanocomposites

Abstract New heterostructures (tetrapods-like shape) were synthesized using AuNPs/CdSe hybrid nanocomposites in a facile synthetic route. The growth mechanism of such heterostructures was based on “Direct Heterogeneous Deposition” mechanism, in which the heterogeneous nucleation growth of CdSe arms (nanorods) structured at the nucleating sites on the surface defects of gold nanoparticles. The heterostructures were characterized using high-resolution transmission electron microscope (HRTEM), high angle annular dark field-scanning transmission electron microscope (HAADF-STEM), energy dispersive X-ray analysis (EDX), absorption, and emission measurements. The proposed growth mechanism was confirmed using HRTEM micrographs. A significant enhancement in the emission properties has been noticed upon the loading of these new heterostructures on reduced graphene oxide (rGO). Fluorescence measurements provided useful insight into the variations in the photophysical properties when rGO is introduced into metal/semiconductor hybrid nanocomposites. The fabricated heterostructures show significant photocatalytic activity in the presence of rGO, compared to pure AuNPs/CdSe tetrapods. It was readily seen that 73.5% of methylene blue (MB) had been degraded by AuNPs/CdSe@rGO tetrapod heterostructures after 80 min of solar irradiation compared to 26.6% and 39% in the absence and presence of AuNPs/CdSe nanocomposites.