Unified description of charge-carrier mobilities in disordered organic semiconductors based on both Arrhenius and non-Arrhenius temperature dependence

Abstract

At present, a lack of consensus on the temperature dependence for charge-carrier mobilities in disordered organic semiconductors hampers progress toward the charge transport model. Many mobility studies on organic semiconductor devices show a universal Arrhenius temperature dependence ln(μ) ∝ 1/T, while other studies, including extended Gaussian disorder model (EGDM), predict a non-Arrhenius temperature dependence ln(μ) ∝ 1/T2. In this paper, we determine the dependence of the charge-carrier mobility on temperature, carrier density, and electric field based on both the effect of the Arrhenius and non-Arrhenius temperature dependence. The description of the mobility can rather well fit the numerical results from a numerical solution of the master equation in the case of both low densities and high densities. Experimental current-voltage characteristics in devices based on organic semiconductor are also excellently reproduced with this unified description of the mobility. It is shown that our description is more applicable for disordered organic semiconductors. Furthermore, we calculate and analyze some electrical properties for the NRS-PPV and OC1C10-PPV polymers in detail based on our method.