Influence of Initial Silver Salt on Surface Structure, SERS Activity, and Surface Stability

In this study, three silver surfaces with morphologies from 0D to 3D were realized by wet‐chemical reduction of mono‐, bi‐ and triatomic silver salts on silicon surfaces. First, we found that the choice of the starting silver salt can influence the formation of silver nanostructures ranging from nanoparticles to dendrites. Second, we found that the surface‐enhanced Raman scattering (SERS) signal is highly dependent on the selected starting silver salt. Using adenine as a test analyte, our studies showed that surfaces with dendritic structures obtained using silver sulfate and phosphate exhibit much higher SERS sensitivity, and that surfaces obtained using silver sulfate have significantly higher chemical stability with respect to oxidation when stored in ambient conditions for 8 weeks compared to standard silver surfaces obtained from silver nitrate. The implementation of synchrotron‐based XPS studies, which allowed the variation of kinetic energy and surface analysis depth profiling, showed that silver nitrate formed surfaces begin significantly to oxidize after 2 weeks, and initially exhibit a heterogeneous surface structure that has a “sandwich”‐like structure, in which oxidized silver phases are present in the metallic silver matrix, compared to pure silver surfaces terminated with sulfate or phosphate groups obtained from silver sulfate or phosphate.