A bipolar charge transport model to simulate the impact of nanometric scale processes on the space charge behaviour in polyethylene

Abstract

Predicting the electric field distribution in polymers used as electrical insulating materials remains the Holy grail, as the presence of charges disturbs the Laplacian electric field. Charges arising from the electrodes are one of the dominant mechanism of charge generation, particularly in polyethylene-based materials. Hence, nanometric scale processes at play at the interface have a non negligible impact on charge injection. In the present study, a bipolar charge transport model developed in 2D is used to simulate the impact of several nanometric scale processes, such as the variation of the barrier height linked to the chemical structure of the material at the interface, as well as surface roughness. Simulation results as regards net charge density, current, but also recombination rate, will be compared to a case where no specific supplementary hypothesis is set at the electrodes. At last, simulations have been performed for a combination of roughness and barrier height variation along the electrode.

High-throughput phase field simulation and machine learning for predicting the breakdown performance of all-organic composites

“…A modified bipolar charge injection and transport model based on the Schottky injection mechanism is established to investigate the charging behavior in polymer/organic molecular semiconductors all-organic polymer composites under high operating voltage [12,20]. The current density at the interface between the electrode and the polymer/organic molecular semiconductors all-organic polymer is presented as [9,12,21],…”

Equivalent transmission line characterization and multi‐layer material measurement analysis of the signal conversion process in the pulsed electro‐acoustic method

“…Similarly, combining with the general solution of Equation ( 6) in plural form, the solution of voltage wave in Equation ( 5) characterizing the transmission line model is shown in Equation (8). u(x, t ) = U (x)e j 𝜔t = A 1 e −𝛼 0 x e j (𝜔t −𝛽 0 x) + A 2 e 𝛼 0 x e j (𝜔t +𝛽 0 x) (…”

“…From the basic equations of acoustic wave propagation in Equation (1) and voltage wave propagation in Equation (6) with their corresponding solutions in Equations ( 3) and (8), it can be found that the characterizations of the two waves are similar. It means that these two wave propagation processes can be equivalent to each other.…”

“…However, limited by the coupling problem between multi-physics modules, it is difficult to construct the models of piezoelectric transducer and amplifier to simulate the whole signal conversion process in PEA measurement. In contrast, the bipolar charge transport model can simulate the spatial and temporal evolutions of space charge under DC and AC electrical stresses [8][9][10]. However, it cannot analyze the effect of the property of measurement system itself on the charge results, that is, it is impossible to discuss the influence of the acoustic signal propagation process on the system.…”