Experimental indication of chemical effects in surface enhanced hyper Rayleigh scattering using dye-adsorbed Ag nanoparticles

We report on the observation of chemical effects in surface enhanced hyper Rayleigh scattering (SEHRS), using silver nanoparticles adsorbed with stilbazolium dyes. The experimental results show that the enhancement factors varied with different donor structures of the dyes, which cannot be explained only according to the electromagnetic effect. Using the extinction spectra and surface enhanced Raman scattering spectra (SERS) to provide the complementary results, we deduce that chemical effects also play an important role in SEHRS in addition to the electromagnetic effect. The chemical effects may be related with the Ag-adsorbate charge transfer transition, similar to the mechanism in SERS.

Research highlights
► Surface enhanced hyper Rayleigh scattering (SEHRS) was measured for four dyes-silver complexes.
► The enhancement factors varied with different donor structures of the stilbazolium dyes.
► Chemical effects play an important role in SEHRS besides to the electromagnetic effect.
► The chemical effects may be related with the silver-adsorbate charge transfer transition.