Numerical Studies of Hopping Transport in Disordered Molecular Solids

Abstract

Photoexcited charge conduction in molecularly-doped polymers can be described in terms of a biased random walk among a set of energetically and spatially disordered molecular centers. We describe a numerical renormalization procedure for studying hopping transport in disordered systems of this type. In this procedure, transport properties of cubic regions drawn randomly from the sample are calculated exactly using equation of motion methods. The original system is then replaced with a new one, defined on a larger length scale, but possessing the same macroscopic transport properties as the original. Fluctuations of the system are smaller at the new length scale, allowing for an accurate calculation of the conductivity using effective medium theory. The approach has been used to study the crossover between nearest-neighbor and variable-range hopping, where it has revealed that the exponential dependence of mobility of the mean interparticle spacing is substantially influenced by the magnitude of the energetic disorder in the system.

Department(s)

Physics

Keywords and Phrases

Biased random walk; Disordered molecular solids; Hopping transport; Molecular doping; Charge transfer; Doping (additives); Mathematical models; Numerical methods; Order disorder transitions; Polymers; Transport properties; Optical materials

International Standard Book Number (ISBN)

978-0819418852

International Standard Serial Number (ISSN)

0277-786X

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1995 SPIE--The International Society for Optical Engineering, All rights reserved.

Publication Date

01 Aug 1995

Link to Full Text

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