Gold nanoelectrodes of varied size: transition to molecule-like charging
A transition from metal-like double-layer capacitive charging to redox-like charging was observed in electrochemical ensemble Coulomb staircase experiments on solutions of gold nanoparticles of varied core size. The monodisperse gold nanoparticles are stabilized by short-chain alkanethiolate monolayers and have 8 to 38 kilodaltons core mass (1.1 to 1.9 nanometers in diameter). Larger cores display Coulomb staircase responses consistent with double-layer charging of metal-electrolyte interfaces, whereas smaller core nanoparticles exhibit redox chemical character, including a large central gap. The change in behavior is consistent with new near-infrared spectroscopic data showing an emerging gap between the highest occupied and lowest unoccupied orbitals of 0.4 to 0.9 electron volt.
Chen
S
S. Chen, R. S. Ingram, M. J. Hostetler, J. J. Pietron, R. W. Murray, Department of Chemistry, Kenan Laboratories, University of North Carolina, Chapel Hill, NC 27599-3290, USA. T. G. Schaaff, J. T. Khoury, M. M. Alvarez, R. L. Whetten, Schools.
Ingram
RS
Hostetler
MJ
Pietron
JJ
Murray
RW
Schaaff
TG
Khoury
JT
Alvarez
MM
Whetten
RL