Electrochemical Quantized Capacitance Charging of Surface Ensembles of Gold Nanoparticles

Abstract

Quantized double layer capacitance charging is observed for monolayers of nanometer-sized monolayer protected gold clusters (Au MPCs) anchored to macroscopic gold electrodes. The clusters were anchored in two ways. One method involves ligand place-exchange binding of an MPC covered with a butanethiolate monolayer to a preformed, self-assembled monolayer of 4,4′-thiobisbenzenethiol (TBBT) on Au. In the second method, an MPC with a mixed TBBT/heptanethiolate monolayer is prepared; this surface-reactive cluster anchors itself onto a gold electrode surface. Differential pulse voltammetry (DPV) of these MPC monolayers displays a succession of current peaks whose regular spacing on the potential axis is similar to that in DPV of solutions of the same, nonanchored MPCs. AC impedance measurements of the MPC monolayers show capacitance undulations that mirror the DPV results.

Absolute Standard Redox Potential of Monolayer-Protected Gold Nanoclusters

“…This determination has been carried out by impedance measurements of a monolayer attached to an Au electrode. 9 Indeed, the capacitance data measured refer to a planar electrode covered by a layer of 4,4′-thiobisbenzenethiol. Even if the capacitance minimum observed is the potential of zero charge, that is, if we assume the absence of any ionic-specific adsorption on the planar gold electrode, it does not necessary mean that the MPCs are neutral.…”

“…[3][4][5][6] At ambient temperature, both freely diffusing and electrode-attached MPCs demonstrate the voltammetric responses featuring a series of evenly spaced current peaks. 4,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] This ensemble behavior is equivalent to a series of classical Coulomb staircase charging events or sequential electrochemical redox reactions, which occur as MPCs encompass an intermediate dimension between small molecules and bulk materials. Previously, the sequential electrontransferhasbeenobservedforfullerene(andderivatives) [22][23][24][25][26] and Pt-carbonyl nanoclusters [Pt n (CO) m ], [27][28][29] which led Weaver et al 30 to develop an electrostatic model to relate the electron transfer energetics of molecular capacitances in gas-and solution-phase systems.…”

Molecular Junctions Composed of Oligothiophene Dithiol‐Bridged Gold Nanoparticles Exhibiting Photoresponsive Properties

“…[21] In our mode, Au-NPs have the unique ability to store electrons [22] and promote the charge separation and facilitate electron transportation [23] within the film during the photocurrent process. Furthermore, the robust coverage and high surface area of the nanostructured film play a key role in this process.…”

Influence of ligand structure on the stability and oxidation of copper nanoparticles

“…Research on nanoparticles has gathered wide attention during the last decade because of their unusual and size-dependent optical [1], magnetic [2] and [3], electronic [4] and [5], and chemical [6] and [7] properties. To fully utilize these properties, the size and shape must be well controlled.…”