1887
banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
Porosity dependence of electron percolation in nanoporous layers
Rent:
Rent this article for
USD
10.1063/1.2837807
/content/aip/journal/jcp/128/6/10.1063/1.2837807
http://aip.metastore.ingenta.com/content/aip/journal/jcp/128/6/10.1063/1.2837807

Figures

Image of FIG. 1.
FIG. 1.

Schematic of changing percolation paths of unpressed (upper) and pressed (lower) porous electrodes due to decrease of porosity.

Image of FIG. 2.
FIG. 2.

Electronic conductivity of a set of nanoparticulate electrodes compressed at different pressures as indicated. The starting thickness of the films is similar in all cases, and all films were sintered after pressing. The conductivity is determined from the current between parallel contacts (Ref. 9), normalizing to the length, width, and thickness of the layer. The original thickness before pressure is taken in all the cases, since there is no change in the amount of present on the electrode.

Image of FIG. 3.
FIG. 3.

Overview of the thicknesses and pressures of the investigated samples.

Image of FIG. 4.
FIG. 4.

Izyumov-Kirkpatrick (Refs. 26 and 28) and Bernasconi-Wiesmann (Ref. 29) analytical models of percolation conductivity for a 3D cubic lattice, in terms of (a) fractional occupation and (b) porosity of the lattice. The straight line indicates the dependence .

Image of FIG. 5.
FIG. 5.

Dependence of on the layer thickness of unpressed electrodes. The solid line gives the dependence for .

Image of FIG. 6.
FIG. 6.

Photocurrent transients of pressed porous electrodes with initial layer thickness of .

Image of FIG. 7.
FIG. 7.

Dependence of on the layer thickness for pressed electrodes with different initial thicknesses. The pressures were 0.2, 0.4, 0.6, and . The dotted line gives the dependence for .

Image of FIG. 8.
FIG. 8.

Dependence of the charge integrated over the diffusion peak on (a) and (b) .

Image of FIG. 9.
FIG. 9.

Dependence of on the porosity of the pressed porous electrodes for the different initial thicknesses. is the critical porosity (0.76). The solid line shows the slope of 2.3.

Image of FIG. 10.
FIG. 10.

Plot of the numerical results obtained by random walk simulation in Ref. 15 as a function of lattice occupancy. The fit to Eq. (7) gives , , and . The diffusion coefficient has been normalized to the value at obtained from the fit.

Image of FIG. 11.
FIG. 11.

Representation of normalized diffusion coefficient as a function of fractional occupation of the lattice. Shown are the Izyumov-Kirkpatrick (Refs. 26 and 28) and Bernasconi-Wiesmann (Ref. 29) percolation theories, the data of Fig. 8 for (except those of ), the numerical data obtained by random walk simulation in Ref. 15, and parabollic fits to the two sets of data following Eq. (15). The diffusion coefficient has been normalized in all cases to the value at obtained from the fits.

Image of FIG. 12.
FIG. 12.

Assumed relationship between porosity, packing fraction, and occupancy according to parameters in Table I.

Tables

Generic image for table
Table I.

Diffusion coefficient in Monte Carlo simulation (Ref. 15) as a function of porosity converted into a fractional occupancy .

Generic image for table
Table II.

Parameters selected for relating porosity with a lattice occupancy.

Loading

Article metrics loading...

/content/aip/journal/jcp/128/6/10.1063/1.2837807
2008-02-11
2014-04-20
Loading

Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Porosity dependence of electron percolation in nanoporous TiO2 layers
http://aip.metastore.ingenta.com/content/aip/journal/jcp/128/6/10.1063/1.2837807
10.1063/1.2837807
SEARCH_EXPAND_ITEM