Incoherent charge hopping and conduction in DNA and long molecular chains

M. Bixon, Joshua Jortner*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

We establish some relations between the kinetics of incoherent, hopping charge transport in bridged large scale chemical systems or in a single-component duplex DNA, and the electrical properties (electric current (j) and conductance (g)) of these systems connected by two electrodes. We considered two distinct voltage distributions across the equienergetic chain (with N bridge elements, and an intersite hopping rate k), which involve the voltage being biased only across the edge bridge elements (case (i)), and the voltage being equally distributed across the bridge (case (ii)). For sufficiently long chains in the low voltage (Φ) domain, we find that j = (ek/N)G(κ1-1)(eΦ/kBT), where G() is a function of charge injection rates κ1-1) to (from) the electrode. The low field (constant) conductance is g = 1.6 × 10-19(k/N)G Ω-1. At high voltages we established the existence of a maximal, constant, Φ independent current (jmax), where g → 0. For case (i) jmax = ek/N, being determined by the intersite hopping rate and by N-1, as appropriate for diffusional charge transport. For case (ii) jmax = eκ1, being independent of the chain length, and determined by the rate of charge injection from the electrode. Finally, we applied our kinetic model for the description of incoherent charge transport in and the electronic properties of a donor-acceptor pair connected by two electrodes.

Original languageEnglish
Pages (from-to)273-282
Number of pages10
JournalChemical Physics
Volume319
Issue number1-3
DOIs
StatePublished - 7 Dec 2005

Funding

FundersFunder number
European grant for Future & Emerging TechnologiesIST-2001-38951

    Keywords

    • Charge transport
    • Conductance
    • Incoherent hole hopping
    • Molecular wires

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