1. High Density, Monodisperse Core-Shell Nanoparticle Arrays: A Study of Nanoscale Catalytic Properties; Regina Ragan, University of California, Irvine -
Overview: Metal nanostructure work function can be varied with size and material interfaces for future correlation of how work function affects activity of catalysts on solid supports
-0.46 eV
-0.94
-0.44 eV
-1.21
1.0
0.6
0.2
0.0 1’ 2’ 3’
Frequency
Decreasing
Work
function
Top: (left to right) Kelvin probe force microscopy (KPFM) images of dysprosium disilicide nanostructures on Si(001). The work function varies with nanostructure feature size. The histograms show the relative work function differences for the three different nanostructures shown in the KPFM images; the Si(001) substrate is included as a reference.
Bottom: The variation of charge transfer from Pd, Pt, and Au atoms to disilicide nanowire surfaces seen in calculated charge density difference images and local density of states (LDOS) calculations predict different noble metals on disilicide nanowires produce a different work function. The next step is to experimentally confirm these predictions using KPFM.
Charge depletion EF
/eV atom
LDOS
states
Fermi
Level
(EF) EF
LDOS
LDOS
Charge
accumulation
Energy (eV)
Energy (eV)
Energy (eV)