Band bending at the interface in Polyethylene-MgO nanocomposite dielectric

TL;DR

This study uses density functional theory to explore the electronic band structure at the interface of polyethylene and MgO in nanocomposites, revealing band bending effects and the impact of silicon treatment on surface states, which informs charge trapping models.

Contribution

First detailed computational analysis of interfacial electronic properties in polyethylene-MgO nanocomposites, highlighting band bending and surface treatment effects.

Findings

Polyethylene conduction band aligns with MgO surface bands.

Band bending creates potential wells up to 2.6 eV deep.

Silicon treatment reduces surface-induced states.

Abstract

Polymer nanocomposite dielectrics are promising materials for electrical insulation in high voltage applications. However, the physics behind their performance is not yet fully understood. We use density functional theory to investigate electronic properties of the interfacial area in magnesium oxide-polyethylene nanocomposite. Our results demonstrate polyethylene conduction band matching with conduction bands of different surfaces of magnesium oxide. Such band bending results in long range potential wells of up to 2.6 eV deep. Furthermore, the fundamental influence of silicon treatment on magnesium oxide surface properties is assessed. We report a reduction of the surface-induced states at the silicon-treated interface. The simulations provide information used to propose a new model for charge trapping in nanocomposite dielectrics.