Understanding insulation failure of nanodielectrics: tailoring carrier energy

Abstract

Owing to the formation of interface and new feature of which, the properties of nanodielectrics can be improved. ‘Hard/soft interface’ and its trap distribution can be tailored by functionalised groups. Molecular simulation results show that the interaction energy and electrostatic potential are larger for the soft interface, which indicates the greater bonding strength with the polymer matrix and electrostatic force on charge carriers. Charge transport simulation indicates that the accumulation of homo‐charges would form a reverse electric field and distort electric field distribution. The injection depth would be restricted at the vicinity of sample/electrodes due to the greater trapping effect of deep traps, thus weakening the distortion in the sample bulk, thereby decreasing carrier energy and delaying the formation of impact ionisation. Based on the accumulation of carrier energy Φ = Eeλ, the idea of suppressing electron free path and carrier energy to enhance the insulation breakdown is confirmed. The classified effects of nanofillers during dc breakdown and corona‐resistant are further understood from carrier energy. The introduced interfacial trap is effective in trapping carriers due to the low carrier energy under dc voltage, while ineffective in blocking the energetic charges during corona‐discharge, but nanoparticles exert blocking and scattering effect against the energetic charges.

Review of interface tailoring techniques and applications to improve insulation performance

“…The trap states in composites or coatings depend on several factors such as bandgap, interfacial structure and volume fractions of fillers, as described in Figure 8. A multiregion model is usually used to describe the interfacial region between the polymer matrix and fillers and can be divided into bonded, transient and normal regions [102][103][104]. A stern layer or interface shell is thought to exist in the bonded region and to form a high-energy barrier for charge injecting the fillers, as shown in Figure 8c-h [103,104].…”

“…A multiregion model is usually used to describe the interfacial region between the polymer matrix and fillers and can be divided into bonded, transient and normal regions [102][103][104]. A stern layer or interface shell is thought to exist in the bonded region and to form a high-energy barrier for charge injecting the fillers, as shown in Figure 8c-h [103,104]. Moreover, deep charge traps can be introduced in filler cores or transient regions.…”

Low‐content metal‐organic framework enhanced interface effect to improve the insulation properties of polyimide‐based composite films

“…In addition to establish the model, researchers also attempted other strategies to explore the mechanisms that the interface enhances the insulation properties. Using the soft/hard interface theory in the composites, Lei et al 11 explored the classification effect of carrier energy in the process of DC breakdown and corona resistance. Wang et al 12 studied the obstruction of breakdown process by the gradient electric field formed at the interface of adjacent layers.…”

Investigation on the Correlation between Dispersion Characteristics at Terahertz Range and Dielectric Permittivity at Low Frequency of Epoxy Resin Nanocomposites

“…Since the concept of "nanodielectrics" was first introduced in 1994 by Lewis, it has attracted much attention due to its superior properties and excellent prospect in the electric industry [1][2][3]. Various enhanced properties of nanocomposites, such as electric strength, mechanical strength, space charge accumulation, and so on, were reported by researchers [4][5][6][7]. Nowadays, it has been generally accepted that most of the superior properties can be attributed to the interface region [8,9].…”