On the Counter-Intuitive Heterogeneous Electron Transfer Barrier Properties of Alkanethiolate Monolayers on Gold: Smooth versus Rough Surfaces

Alkanethiolate monolayers formed on rough gold surfaces can, somewhat surprisingly, act as stronger barriers to heterogeneous electron transfer than those on smooth gold surfaces. This paper presents a possible explanation for this observation by constructing simple geometric models of a rough and smooth gold surface to examine how microscopic roughness differences can affect the nucleation/growth of the adlayer and size/density of structural defects. Expectedly, the number of defects predicted for adlayers formed on smooth gold is lower than any of those for rough gold. The counter-intuitive result is that the sizes of a small portion of the defects in the adlayer on the smooth surface are larger than any of those found on the rough surface. The potential implications of these results are discussed.

Automated summary

The roughness of the gold surface can affect the properties of alkanethiolate monolayers as barriers for electron transfer, as shown in the formation of the adlayer and the size and density of structural defects.