Electrochemical Study of Adlayers of alpha,omega-alkanedithiols on Au(111): Influence of the Forming Solution, Chain Length and Treatment with Mild Reducing Agents

FERNANDO P. COMETTO; CECILIA A. CALDERÓN; ESTEBAN M. EUTI; DANIELA K. JACQUELIN; MANUEL A. PEREZ; EDUARDO M. PATRITO; VICENTE A. MACAGNO

JOURNAL OF ELECTROANALYTICAL CHEMISTRY - (Print)

ELSEVIER SCIENCE SA

Año: 2011 vol. 661 p. 90 - 99

1572-6657

Self-assembled adlayers of alkanedithiols (DTs) on Au(1 1 1) are studied with electrochemical techniques (reductive desorption experiments, redox couples cyclic voltamperometry and electrochemical impedance spectroscopy) in order to characterize adlayer structures. The formation of intralayer and interlayer disulphide bonds (S?S) strongly affects the structure of the layers. We considered different variables which influence the amount of S?S bonds: the length of the alkyl chain (from 2 to 9 C atoms), the polarity of the solvent of the forming solution (ethanol, n-hexane and toluene), the O2 level and the use of a post-deposition treatment with mild reducing agents. Optimal experimental conditions for the formation of DT monolayers with controlled amount of S?S bonds for both short and long alkyl chains are precisely identified. According to our results, short chain DTs form multilayer structures (interlayer S?S bonds) under typical procedures; whereas long chain DTs present intralayer S?S bonds. The use of low polarity solvents during the layer formation as well as the use of reducing agents after deposition favours the formation of good quality DT monolayers.