Electrodeposition of Palladium onto a Pyridine-Terminated Self-Assembled Monolayer

Christophe Jean Claude Silien, Dorothée Lahaye, Marco Caffio, Renald Schaub, Niel R. Champness, Manfred Buck

Research output: Contribution to journalArticlepeer-review

Abstract

The electrodeposition of Pd onto self-assembled monolayers (SAMs) of 3-(4-pyridine-4-yl-phenyl)-propane-1-thiol on Au(111) has been investigated by scanning tunneling microscopy. Two schemes are compared, one involving an established two step procedure where Pd2+ ions are first coordinated to the pyridine moieties and subsequently reduced in Pd2+-free electrolyte. The second deposition routine involves electroreduction in an electrolyte containing low concentration of Pd2+ which merges both steps and, thus, significantly simplifies metal deposition onto pyridine-terminated SAMs. Both strategies produce identical Pd nanoparticles (NPs) which exhibit a narrow size distribution and an apparent STM height of 2.4 nm. The observation of a Coulomb blockade and easy displacement of the nanoparticles in STM experiments evidence deposition on top of the SAM. The NPs are concluded to be essentially spherical. Growth of the NPs is found to be self-limiting since repeating the complexation-deposition cycle increases the density of the nanoparticles rather than their size but only close to monolayer coverage. At high concentration of thePd2+ electrolyte, deposition on top of the SAM is impeded by a competitive mushroom-type growth.

Original languageEnglish
Pages (from-to)2567-2574
Number of pages0
JournalLangmuir
Volume27
Early online date21 Feb 2011
DOIs
Publication statusPublished - 2011

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