Random walk numerical simulation for hopping transport at finite carrier concentrations: diffusion coefficient and transport energy concept

文献情報

出版日 2009-09-23

DOI 10.1039/B912935A

インパクトファクター 3.676

著者

J. P. Gonzalez-Vazquez, Juan A. Anta, Juan Bisquert

原文を見る

要旨

The random walk numerical simulation (RWNS) method is used to compute diffusion coefficients for hopping transport in a fully disordered medium at finite carrier concentrations. We use Miller–Abrahams jumping rates and an exponential distribution of energies to compute the hopping times in the random walk simulation. The computed diffusion coefficient shows an exponential dependence with respect to Fermi-level and Arrhenius behavior with respect to temperature. This result indicates that there is a well-defined transport level implicit to the system dynamics. To establish the origin of this transport level we construct histograms to monitor the energies of the most visited sites. In addition, we construct “corrected” histograms where backward moves are removed. Since these moves do not contribute to transport, these histograms provide a better estimation of the effectivetransport level energy. The analysis of this concept in connection with the Fermi-level dependence of the diffusion coefficient and the regime of interest for the functioning of dye-sensitised solar cells is thoroughly discussed.

掲載誌

Physical Chemistry Chemical Physics

CiteScore: 5.5

自己引用率: 10.3%

年間論文数: 3036

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