Quantum-Influenced Anomalous Electron Transport Induced by Heterocyclic Aromatic Pendants in Polyolefin Dielectrics.

Abstract

It is generally acknowledged that trap-governed charge transport underlies the dielectric properties of polyolefin dielectrics. However, in heterocyclic aromatic pendant-grafted polypropylene, we observe anomalous phenomena that cannot be accounted for by trap theory, including a discrepancy between the trap depth and the observed dielectric performance. Notably, space charge measurements indicate the presence of micrometer-scale electron transport, far exceeding the nanoscale confinement predicted by trap theory. These counterintuitive phenomena are suggested to arise from quantum transport, a mechanism that has been largely overlooked in polymeric dielectrics. By combining nonequilibrium Green's function-density functional theory (NEGF-DFT) with electron trapping-detrapping analysis, we demonstrate that heterocyclic moieties simultaneously regulate local trapping-detrapping processes and affect long-range quantum transport. Particularly, quantum transport may offer a plausible nonlocal pathway enabling the electron propagation over micrometer-scale distances. These findings broaden the conventional understanding of charge transport in polyolefins and provide a new dimension for the rational design of polymeric dielectrics.