Au Films Composed Of Nanoparticles Fabricated On Liquid Surfaces For Sers

A series of Au films with different nominal deposition thickness d were fabricated on ionic liquid surfaces by thermal evaporation at room temperature, taken as surface-enhanced Raman scattering (SERS) substrates. Au atoms deposited on the liquid surfaces can diffuse and aggregate randomly and eventually form films with ramified structure, which consist of nanoparticles (NPs). There are amounts of ultrasmall (similar to 1 nm or smaller) nanogaps among the Au NPs, which can dramatically enhance Raman signal. Raman spectra of R6G were investigated with the assistance of the Au films. The results indicate that the Au films with higher thickness possess better SERS performance when 5.0 <= d <= 30.0 nm. A random distribution model of Au NPs was used in the finite-difference time-domain method and the simulation results are in good agreement with the experimental findings.