No abstract

Gold nanospheres and gold nanorods of different sizes have been synthesized by a seed-mediated growth approach. They have been characterized by TEM, UV-Vis spectroscopy, and the photothermal effect of spheres have been tested. By adding a dimethylformamide solution of polyvinylpyrrolidone and tetrachloroauric acid to the nanoparticles, an interesting nano-shape, composed of a quasi-spherical core with copious spikes (core size ranging from 50 to 100 nm and spikes from 15 to 50 nm) - just remembering the sea urchins - has been obtained. Depending on the starting sample of nanoparticles (spheres or rods), the size of the core changes, while there are slight variations of the spikes. Plasmonic features in the visible to IR range of the electromagnetic spectrum have been recorded, and it was observed an increase of the photothermal effect by increasing the nanourchins core dimensions.