Induced Surface Enhancement in Coral Pt Island Films Attached to Nanostructured Ag Electrodes

摘要

Coral Pt islands films are deposited via electrochemical reduction on silicacoated nanostructured Ag electrodes. From these devices surface enhanced(resonance) Raman [SE(R)R] signals of molecules exclusively attached to Pt areobtained with intensities up to 50% of the value determined for Ag. SE(R)Rspectroscopic investigations are carried out with different probe molecules,silica coating thicknesses and excitation lines. Additionally, fieldenhancement calculations on Ag-SiO2-Pt support geometries are performed toelucidate the influence of the Pt island film nanostructure on the observedRaman intensities. It is concluded that the non perfect coating of the Ptisland film promotes the efficiency of the induced Pt SER activity. Comparisonwith similar measurements on Ag-SiO2-Au electrodes further suggests that thechemical nature of the deposited metal island film plays a minor role for theSE(R)R intensity.