Open Access Nano Express

A High Diffusive Model for Nanomaterials

P Di Sia12* and V Dallacasa13

Author Affiliations

1 Department of Computer Science, Faculty of Science, Verona University, Strada Le Grazie 15, 37134, Verona, Italy

2 Faculty of Computer Science, Free University of Bozen, Piazza Domenicani 3, 39100, Bozen-Bolzano, Italy

3 Accademia Nazionale dei Lincei, via della Lungara 10, Rome, Italy

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Nanoscale Res Lett 2011, 6:39  doi:10.1007/s11671-010-9783-y

Published: 28 September 2010

Abstract

Considerable attention is today devoted to the engineering of films widely used in photocatalytic, solar energy converters, photochemical and photoelectrochemical cells, dye-sensitized solar cells (DSSCs), to optimize electronic time response following photogeneration. However, the precise nature of transport processes in these systems has remained unresolved. To investigate such aspects of carrier dynamics, we have suggested a model for the calculation of correlation functions, expressed as the Fourier transform of the frequency-dependent complex conductivity σ(ω). Results are presented for the velocity correlation functions, the mean square deviation of position and the diffusion coefficient in systems, like TiO2 and doped Si, of large interest in present devices. Fast diffusion occurs in short time intervals of the order of few collision times. Consequences for efficiency of this fast response are discussed in relation to nanostructured devices.

Keywords:
Correlation Functions; Diffusion; Frequency-Dependent Complex Conductivity; Nanostructures; Semiconducting Oxides; Montecarlo Simulation