Grafting oligothiophenes on surfaces by diazonium electroreduction: a step toward ultrathin junction with well-defined metal/oligomer interface

• Type: Article in International Scientific Journal
• Date: 2009-10-21

Authors

Verena Stockhausen (Author) FEUP; Jean Christophe Lacroix (Author) Other; Jalal Ghilane (Author) Other; Pascal Martin (Author) Other; Gaelle Trippé-Allard (Author) Other; Hyacinthe Randriamahazaka (Author) Other

Journal

Title: Journal of the American Chemical Society

Vol. 131 No. 41

Pages: 14920-14927

ISSN: 0002-7863

Publisher: American Chemical Society

Indexing

ISI Web of Science

Scopus

Other information

DOI: 10.1021/ja9047009

Abstract (EN): : The functionalization of electrode materials through diazonium electroreduction using a heteroaromatic compound, without phenyl groups, has been investigated for the first time. The electrochemical reduction of 2-aminoterthiophenyldiazonium cation, generated in situ, coats the electrode (glassy carbon (GC), gold or platinum) with an ultrathin organic layer, shown by X-ray photoelectron spectroscopy (XPS) of that deposited on gold to consist of terthiophene or oligothiophene. The coating is electroactive at potential close to that of terthiophene in solution. The electrochemical response of the modified GC electrode in the presence of various reversible redox couples shows that the attached layer acts as a conductive switch. It behaves as a barrier to electron transfer when the standard redox potential is below 0.5 V/SCE; in this case diode-like behavior is observed. However, for more oxidizing redox probes the layer can be considered as transparent and no barrier effect is observed. The layer deposited on a platinum ultramicroelectrode (UME) behaves similarly to that obtained on the large GC electrode. Scanning electrochemical microscopy (SECM) can be performed using this electroswitchable modified platinum UME which can act as a filter toward competitive redox exchange pathways.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8