第一原理計算に基づくPETオリゴマー中電子正孔輸送のシミュレーション

抄録

Recently, we have developed a first-principles based multi-scale modeling approach for studying carrier transport properties in polymeric dielectric, and have successfully modeled hole transfer in polyethylene (PE). In this study, in order to see if we can model carrier transport in more complex polymers, we have utilized the multi-scale modeling method to simulate electron and hole transfer in polyethylene terephthalate (PET). The agreement between computed and experimental electron and hole mobilities in PET demonstrated the robustness of the modeling technique. The multi-scale modeling approach enabled us to understand the microscopic origin of the carrier transport properties; unlike carrier transport in PE where the energetic disorder is dominated by the conformational disorder of the polymer chain, that in PET was strongly affected by the electrostatic disorder (disorder of the electrostatic potential due to surrounding environment). It is shown that this difference comes from the fact that (1) the charge localized region in PE chain is determined by the conformational disorder whereas that in PET is determined by the chemical structure of the polymer chain, and (2) PET chain has large local dipole compared to PE chain.