SURFACE DYNAMICS DURYNG THE OXIDATIVE ADSOPRTION OF ALKANETHIOLS ON COPPER. AN IN-SITU STM INVESTIGATION

OJEDA, CLAUDIO; PATRITO, E. MARTIN

Mar del Plata

Simposio; FOURTH LATIN AMERICAN SYMPOSIUM ON SCANNING PROBE MICROSCOPY; 2007

In-situ STM was employed to investigate the dynamics of polycrystalline copper surfaces during the oxidative adsorption of 1-octanethiol from NaOH electrolyte while keeping the electrode at negative potentials, thus preventing any oxide growth. Upon addition of 1-octanethiol to the STM cell, a rich surface dynamics is observed: the faceting of the surface and the collapse of metallic grains could be followed in real time. The surface becomes stable after approximately two hours of immersion in the thiol solution. A progressive smoothing of the surface is observed during the formation of the self assembled monolayer on the polycrystalline copper surface.             Oxidation of the copper surface in NaOH + 1-octanethiol solutions leads to the formation of crystalline copper oxide which upon reduction produces atomically flat Cu(111) terraces with monatomic step heights.             Periodic density functional calculations were performed to explained the enhanced surface dynamics during the adsorption of alkanethiols.