Transport level in disordered organics: An analytic model and Monte-Carlo simulations

Transport level concept is known as a promising tool which provides great simplification in analytic description of hopping transport in organics. However, quantitative modeling of mobility and diffusion coefficient by the use of this concept is extremely rare up to the moment. Monte-Carlo modeling of transport level and related quantities in the framework of Gaussian disorder model is carried out in this work. Methodology of this modeling is discussed and physical essence of various approaches to transport level is clarified. It is shown that an analytic model, which considers the transport level as the average energy of states from which a carrier can be released by means of energetically upward and downward jumps with equal probability, is applicable for quantitative modeling of temperature dependence of mobility and coefficient of field-stimulated diffusion. Simple analytic expressions for these transport coefficients are obtained. (C) 2014 AIP Publishing LLC.