Silver ions adsorbed to self-assembled monolayers of alkanedithiols on gold surfaces form Ag-dithiol-Au multilayer structures

Double-ended alkanedithiols, 1,9-nonanedithiol and 1,5-pentanedithiol. form ed self-assembled monolayers (SAMs) on Au(111) substrates and were used to adsorb silver ions from an ethanolic solution of silver nitrate and formed Ag-dithiol-Au multilayer structures. Ellipsometry, contact angle measuremen t and X-ray phototelectron spectroscopy (XPS) confirmed that the alkenedith iol molecules formed SAMs with only one-ended thiol groups attached to the Au substrates, which was supported by molecular mechanics calculation. XPS and X-ray Auger electron spectroscopy (XAES) indicated that silver ions wer e deposited onto the SAMs from the solution by the chemical reaction of sil ver nitrate with another-ended thiol groups of the SAMs. Atomic force micro scopy (AFM) was used to observe SAMs and multilayer structures.