Size and Temperature Effects on the Surface Plasmon Resonance in Silver Nanoparticles

Abstract

The surface plasmon energy in spherical silver nanoparticles embedded in silica host matrix depends on the size and temperature of the nanoparticles. The depend- ences of the surface plasmon energy were studied for silver nanoparticles in the size range 11-30 nm and in the temper- ature interval 293-650 K. As the size of the nanoparticles decreases or the temperature increases, the surface plasmon resonance shifts to red. When the size of the nanoparticles decreases, the scattering rate of the conduction electrons increases, which results in the nonlinear red shift of the surface plasmon resonance. The red shift with temperature is linear for larger nanoparticles and becomes nonlinear for smaller ones. As the temperature of the nanoparticles increases, the volume thermal expansion of the nanopar- ticles leads to the red shift of the surface plasmon resonance. The thermal volume expansion coefficient depends on the size and temperature. It increases with a decrease of the nanoparticle size and an increase of the temperature.