Effect of media on plasmon resonance of silver nanoparticles

The effect of the dielectric and chemical properties of the surrounding medium on the extinction spectra of silver island films is determined. The shift of the plasmon resonance maximum towards low energies with an increase in the permittivity of the medium (for SiO2 and Al2O3) corresponds to the calculated value, essentially depending on the shape of nanoparticles. Simultaneously with the shift, an increase in the optical density at the plasmon resonance frequency is observed. For nanoparticles immersed in an anisotropic medium, liquid crystal in particular, the shift of the plasmon resonance maximum depends on the local permittivity in the immediate vicinity of nanoparticles, i.e., on how exactly the surrounding molecule interacts with the substrate and the nanoparticle. In this case, the displacement can either be completely absent or be significantly greater than the displacement in isotropic media, depending on the shape of nanoparticles. The increase in optical density also depends on the local permittivity. The partial oxidation of nanoparticles leads to an insignificant but noticeable shift towards higher energies. In this case, the plasmon lifetime in the nanoparticle increases.