The redshift of surface plasmon resonance of colloidal gold nanoparticles induced by pressure with diamond anvil cell

Abstract

Colloidal gold nanoparticles, extensively reagent-purified free and well size-controlled monodisperse, are chosen to study Surface Plasmon Resonance (SPR) under pressure with both in situ experimental measurements and theoretical calculations. The refractive index of water is enhanced by pressure up to 1.2 GPa, while the size, shape, and permittivity of gold nanoparticles change insignificantly. A redshift is shown in the absorption spectrum of gold nanoparticles during the process of increasing pressure and the absorption peaks corresponding to SPR of gold nanoparticles is found to be a linear dependence on the refractive index of water under pressure. It is very important to evaluate the wavelength of the absorption spectrum while we explore the phase transition of materials under pressure with surface enhanced Raman spectroscopy based on gold nanoparticles. These results provide us another method of tailoring SPR with pressure and enhancing the efficiency of detecting the weak optical signal under high pressure.