Molecular Simulation Study on Thermal Property and Electron Property of Polypyrrole/ Nitrogen‐modified Graphene Composites

ABSTRACT To design high performance of organic/inorganic thermoelectric composite materials by molecular simulation, composite materials (PPy/NG) are constructed by incorporating graphene (GE) modified with N atoms (NG) into the Polypyrrole (PPy) matrix. For different GE doping concentrations and different concentration N atoms modified in GE (mod‐Ns), the thermoelectric properties of PPy/ n ‐NG composite materials ( n represents different N atoms modified concentration) is systematically investigated using the non‐equilibrium molecular dynamics (NEMD) and density functional theory (DFT). It is found that N‐modification on GE has a significant influence on the reduction on the thermal conductivity of composites with 7.06 wt.% graphene concentration. Moreover, when the mod‐Ns concentration reached 3.66%, the thermal conductivity of the PPy/NG composite material is decreased by 49.19%. Additionally, the electron properties of PPy/ n ‐NG are studied. It is found that the energy differences between the HOMO of n ‐NG and the LUMO of PPy decrease with the increase of mod‐Ns concentration in NG. Overall, this study reveals that n ‐NG reduces the thermal conductivity of PPy/ n ‐NG composites and promotes the transfer of electrons between n ‐NG and PPy. It establishes a theoretical foundation for designing high‐performance organic/ inorganic thermoelectric materials.