Exploring the universality of the alternating conductivity of disordered materials using the Gaussian distribution of activation energies.
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Date
2019
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Abstract
This paper presents a newapproach for the analysis of ACconductivity, s*(w)= s¢(w)+is(w), in
disordered solids which brings together the quasi-universal frequency-dependent conductivity and
the idea of a Gaussian distributions of probable activation energy barriers for hopping carriers. An
explicit expression forAC conductivity was obtained using a complex dielectric response function and
a continuous time random walk treatment applied to a lattice obeying the Kubo’s fluctuationdissipation
theorem. This expression provides an insight into the universality of the form
s¢(w) μ ws (0 s 1) and s(w) μ kw (k is the dielectric constant), aswell into the effect of the
Gaussian disorder on exponent s.We discuss the similarities and differences with the Random Free
Energy Barrier model equivalent to the long-used box model, and it brings support to an extending
expression proposed by JCDyre and one of the authors. The applicability of the model to
experimental observations on poly[(2-methoxy-5-hexyloxy)-p-phenylenevinylene] reveals the dielectric
constant, mean energy and variance of the Gaussian distribution for hopping carriers in this
disordered conjugated polymer.
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Keywords
Hopping transport, Organic semiconductors, Conductivity phenomena in semiconductor
Citation
COUTO, J. D.; SANTOS, M. de C.; BIANCHI, R. F. Exploring the universality of the alternating conductivity of disordered materials using the Gaussian distribution of activation energies. Materials Research Express, v. 6, n. 4, p. 1-8, 2019. Disponível em: <https://iopscience.iop.org/article/10.1088/2053-1591/aad1ce>. Acesso em: 19 mar. 2019.