Atomistic modeling of charge transport in polyethylene

摘要

The electrical degradation and breakdown in polymeric insulators are correlated with the conduction of charge carriers in the material. However carrier transfer in polymeric insulators remains poorly understood. In order to investigate the relation between the morphology and the carrier mobility of polymeric insulators, hole mobilities in crystalline and amorphous PE was evaluated with multi-scale computational approaches. It is shown that high hole mobility (~ 10-2 cm2/Vs) in crystalline PE, despite the small electronic couplings is due to the small reorganization energy, which is realized through the intra-molecular hole delocalization, and due to quantum nuclear tunneling. In contrast, owing to the (1) large reorganization energy due to the short persistence length of PE chains and (2) the large energetic disorder due to the conformational disorder of PE chains, the hole mobility in amorphous PE is several orders of magnitude smaller than that in crystalline PE.