Unified Description of Charge-Carrier Mobilities in Disordered Semiconducting Polymers

Group Polymer Physics, Eindhoven Polymer Laboratories and Dutch Polymer Institute, Technische Universiteit Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Physical Review Letters (Impact Factor: 7.51). 06/2005; 94(20):206601. DOI: 10.1103/PhysRevLett.94.206601
Source: PubMed

ABSTRACT From a numerical solution of the master equation for hopping transport in a disordered energy landscape with a Gaussian density of states, we determine the dependence of the charge-carrier mobility on temperature, carrier density, and electric field. Experimental current-voltage characteristics in devices based on semiconducting polymers are excellently reproduced with this unified description of the mobility. At room temperature it is mainly the dependence on carrier density that plays an important role, whereas at low temperatures and high fields the electric field dependence becomes important. Omission in the past of the carrier-density dependence has led to an underestimation of the hopping distance and the width of the density of states in these polymers.

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Available from: W.F. Frank Pasveer, Sep 29, 2015
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    • ", [62]. On the other hand, it has been shown that a Gaussian DOS is suitable for describing intrinsic energetic distribution of states in a disordered organic semiconductor [63], [64]. The characteristic carrier-density-dependence of hopping mobility in Gaussian DOS is expected to be directly linked to V GS -dependent mobility in OFETs. "
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    • "solutions of the master equation coupled with the Poisson equation . The considered master equation model is exactly the same on which the state-of-the-art stationary modeling of transport in organic materials is based [17], [18], [27]. We describe a fully coupled numerical approach to this model which is applicable to the transient simulation. "
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    • "In this case, λ would mirror the dielectric property of the organic semiconductor. We infer that the electric field dependence of mobility, which is characteristic of disordered organic materials, can also have an effect on λ in connection with the degree of disorder in the distribution of states [24]. A standard way to model the finite output conductance behavior is to multiply the total current by (1 + λV DS ) [8]. "
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