OPTICAL AND ELECTROCHEMICAL STUDY OF THE SULPHIDE SILVER SYSTEM/

The behaviour of suphide species at a silver/electrolyte interface alo ng with the electrodeposition of thin Ag2S films have been studied by a combination of electrochemical and in situ optical methods. The pote ntial region between - 1.08 and - 0.470 V (nhe), pre-peak zone, is mai nly characterized by a reversible process, at -0.870 V, overlapping an d catalysing the her, ascribed to the formation of an Ag-(SH-)(ads) bo nd. Phase Ag2S deposits were found to fit a linear relationship betwee n reflectance, in the blue region, and charge. The oxidation of surfac e Ag2S (postwave) is readily observed by differential reflectance at p otentials positive of the onset of bulk Ag2S formation. The rough sliv er surface brought about by the reduction of Ag2S allows a strong coup ling between photons and surface plasmons.