Journal of Physical Chemistry B 2006-01-26

Surface microscopic structure and electrochemical rectification of a branched alkanethiol self-assembled monolayer.

Qijin Chi, Jingdong Zhang, Jens Ulstrup

Index: J. Phys. Chem. B 110(3) , 1102-6, (2006)

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Abstract

The tert-butanethiol self-assembled monolayers (SAMs) on Au(111) surfaces were prepared from various solvents and investigated by a combination of scanning tunneling microscopy (STM) and electrochemistry in aqueous environments. High-resolution STM images reveal a (radical(7) x radical(7))R19 degrees surface lattice structure, in contrast with the conventional lattice (radical(3) x radical(3))R30 degrees structure for straight-chain alkanethiol SAMs. Interestingly, such a branched monolayer shows electrochemical rectification toward redox probes. We suggest that electrochemical rectification could be a general characteristic of short-chain branched alkanthiol SAMs, and originate in localized electronic effects.