Photothermal effects in SiO2@Au core-shell nanoparticles have demonstrated great potential in various applications for drug delivery, thermo-photovoltaics and photothermal
cancer therapy, etc. However, the photothermal conversion of SiO2@Au nanoparticles partially covered by disconnected
gold clusters has rarely been investigated systematically. Here, we control the surface morphology of
gold clusters on the photothermal conversion performance of SiO2@Au core-shell nanoparticles by means of chemically adjusting the synthesis parameters, including amounts of
gold salts, pH value and
reducing agent. The macroscopic variations of the photothermal heating of different nanoparticle dispersions are significantly influenced by the nanoscale differences of
gold cluster morphologies on the
silica core. The temperature rise can be enhanced by the strong near-field coupling and collective heating among
gold clusters with a relatively uniform distribution on the
silica core. A numerical model of the simplified photothermal system is formulated to interpret the physical mechanism of the experimental observation, and shows a similar trend of temperature rise implying a reasonably good agreement with experimental data. Our work opens new possibilities for manipulating the light-to-heat conversion performance of SiO2@Au core-shell nanoparticles and potential applications of heat delivery with spatial resolution on the nanoscale.