Studies of Structure and Reactivity in Monolayer Assemblies: 1. Ozonolysis of Alkanethiolate Self Assembled Monolayers on Au. 2. In-Plane Resistivity of Ultrathin Gold Films as a High Sensitivity, Molecularly Differentiated Probe of Chemisorption at the Liquid-Metal Interface

Ultrathin gold films, with thicknesses between the onset of conductivity (d ∼ 5 nm) and the electron mean free path ( d ∼ 80 nm), display surface-sensitive resistivities, which have been exploited to follow the adsorption and desorption of molecular monolayers at the metal solution interface with high precision. For nominal Au film thicknesses (d ∼ 40 nm), strongly chemisorbed thiolate monolayers increase the resistivity of the thin Au films by ca. 4%, but weakly adsorbed species, such as pyridine or phenolate at open circuit, induce no observable change in the Au film resistance. Resistivity measurements implemented with a high stability current source and high-precision digital voltmeter sampling at 1 Hz resulted in 3 sigma uncertainties in alkanethiolate coverage of 1.4 x 10--4 monolayer. Correlating chemical manipulations with changes in surface morphology as characterized by AFM indicates a significant morphology-related contribution to resistivity which must be controlled to extract meaningful information related to the electronic interaction of adsorbate and substrate.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Zhang, Yumo

Contributors dc:contributor

• Bohn, Paul W.

• Chemistry, Analytical

Language dc:language

eng

Identifier

(MiAaPQ)AAI9953187

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/84462