Optical properties and photo-heating of aqueous suspensions of silicon-based nanocomposite particles with deposited gold

The optical properties of nanocomposite particles consisting of silicon cores about 100 nm in size with smaller gold nanoparticles deposited on their surface have been studied. An increase in the absorption of light in the near-infrared region of the spectrum for the obtained nanoparticles is observed in comparison with that for nanoparticles of pure silicon or gold. Experiments on measuring the temperature of aqueous suspensions showed significantly higher rates of photoheating of nanocomposite particles upon irradiation with laser radiation at a wavelength of 810 nm compared to the case of pure silicon nanoparticles. Calculations of the distribution of the electric field showed multiple increases in its strength near nanocomposite particles upon irradiation with light in the visible and near-infrared ranges and also made it possible to find the scattering and absorption contributions to the extinction spectra of nanoparticle suspensions. The observed enhanced photoheating of nanocomposite particles can be used for application in antibacterial treatment and cancer hyperthermia.