Evaluation of Charge Mobility in Organic Materials: From Localized to Delocalized Descriptions at a First-Principles Level

Authors

  • Zhigang Shuai,

    Corresponding author
    1. Key Laboratory of Organic OptoElectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, 100084 Beijing, PR China
    • Key Laboratory of Organic OptoElectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, 100084 Beijing, PR China.
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  • Linjun Wang,

    1. Key Laboratory of Organic OptoElectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, 100084 Beijing, PR China
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  • Qikai Li

    1. Key Laboratory of Organic Solids, Beijing National Laboratory for Molecular Science (BNLMS) Institute of Chemistry, Chinese Academy of Sciences, 100190 Beijing, PR China
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Abstract

The carrier mobility for carbon electronic materials is an important parameter for optoelectronics. We report here some recently developed theoretical tools to predict the mobility without any free parameters. Carrier scatterings with phonons and traps are the key factors in evaluating the mobility. We consider three major scattering regimes: i) where the molecular internal vibration severely induces charge self-trapping and, thus, the hopping mechanism dominates; ii) where both intermolecular and intramolecular scatterings come to play roles, so the Holstein-Peierls polaron model is applied; and, iii) where charge is well delocalized with coherence length comparable with acoustic phonon wavelength, so that a deformation potential approach is more appropriate. We develop computational methods at the first-principles level for the three different cases that have extensive potential application in rationalizing material design.

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