Parametrization of the Charge-Carrier Mobility in Organic Disordered  Semiconductors. APAE against EGDM.

                       S. D. Baranovskii^1,2, A.V. Nenashev¹, D. Hertel², F. Gebhard¹ and K. Meerholz² 

¹Faculty of Physics, Philipps-Universität Marburg, Marburg 35032, Germany
²Department für Chemie, Universität zu Köln, Köln 50939, Germany

A correct parametrization of charge-carrier mobility in organic disordered semiconductors is of vital importance for device simulations. Theoretical equations for charge carrier mobility μ(T, n, F), dependent on the concentration of carriers n, on temperature T, and on the applied electric field F, are at the heart of the simulation algorithms. So far, most of the algorithms, including the commercially distributed software packages, are based on the so-called EGDM equation [1].  However, the EGDM equation is not compatible with the basic theoretical concepts for hopping transport in disordered materials [2-3]. Parameters in this equation are not relevant for the effects, while the relevant parameters are missing in the EGDM equation [4, 5]. 

Although μ(T, n, F) can be easily accessed analytically in the form of a simple closed-form system of equations, as has been highlighted in the Mott Lecture at ICANS27 [5], this solution has not yet become a state of the art for the community dealing with device simulations. 

In the presentation, we show that μ(T, n, F) in organic disordered semiconductors can be described, in a wide range of material parameters, by a single appropriately parameterized analytical equation (APAE) [6]. Straightforward computer simulations confirm the validity of the APAE [6]. The APAE is user-friendly and, thus, suitable for incorporation into device-simulation algorithms.

[1] W. F. Pasveer, et al. Phys. Rev. Lett. 94, 206601 (2005).
[2] N. F. Mott, Phil. Mag. 19, 835 (1969).

[3] B. I. Shklovskii, Sov. Phys. Semicond. 6, 1964 (1973). 
[4] J. O. Oelerich, D. Huemmer, and S. D. Baranovskii, Phys. Rev. Lett. 108, 226403 (2012).

[5] S. D. Baranovskii, Phys. Stat. Sol. A 215, 1700676 (2018).

[6] arXiv:2311.05406v1 (2023) (https://arxiv.org/abs/2311.05406).