Dielectric controlled local field resonance distribution in Au/Pd Core/shell nanostructure: A mechanism based on local field enhancement

摘要

The nanostructure of bimetallic Au/Pd particles was fabricated in the study to investigate their local surface plasmon resonance(LSPR) shift and local field factor.The LSPR was detected according to the structure, electric dipole and multipole electrical quadrupole moment.It was found that the symmetric coupling red shifts decreased obviously with the increase of the shell thickness and the nanoparticle size, and the absorption efficiencies of the nanostructure depended on the LSPR resonance frequency.Moreover, the LSPR and the local field were measured with annular limited optical distribution in terms of dipole resonance mode and resonance frequency.It was indicated that the resonance scattering has been changed in spite of the Au/Pd deformation and the collective plasmon enhancement.Besides, the single particle in Z direction went up with their relative core and shell dimension;the vertical electric field obtained the same maximum value as the horizontal electrical field;the electromagnetic field decayed inside the material and most of the input radiation energy was reflected back in the particle diagonal.The solid structures of the Au/Pd Core/shell nanoparticles were measured by TEM and EDS.