Different quantum optical response in fluorescence of gold and silver nanoparticles

Electrical permittivity and fluorescence emission behavior of gold and silver nanoparticles with radii range from 1 to 10 nm are studied in quantum mechanical regime and compared with classical results. It is observed that electrical permittivity of gold and silver nanoparticles is significantly modified considering quantum mechanical effects. Furthermore, it varies by wavelength while the size of nanoparticles decreases. The results indicate clear blue shift for silver and red shift for gold and also weakening of fluorescence peaks for both types of nanospheres. These quantum plasmonics particles which can pass through walls of living cells due to their small size can also serve as a fluorescent probe and delivery system for imaging and targeted delivery of bio-systems.