Investigation of surface trap distribution in LDPE/SiO2 nanocomposite based on simultaneous observation of space charge and relaxation current

Wang, Yalin; Wu, Jiandong; Yin, Yi

doi:10.1109/tdei.2016.006018

Cited by 20 publications

(12 citation statements)

References 24 publications

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“…For example, Huang's group prepared various morphologies (i.e. cube, rhombic dodecahedra and octahedra) of Ag 2 O [39] and Cu 2 O [40] that preferentially exposed (100), (110) and (111) facets, respectively. The cubic Ag 2 O showed the highest photoactivity toward the degradation of methyl orange molecules (MO), followed by octahedra and rhombic dodecahedra shapes.…”

Section: Different Interpretations Amongst Researchersmentioning

confidence: 99%

“…Recently, the calcination removal of fluorine has been shown to cause stacked TiO 2 nanosheets along particle [001] crystallographic direction, driven by the minimization of surface energy. [110,111] The surface Ti-F groups can be totally hydrolysed by water during calcination in air at high temperature (600°C, endothermic reaction) ( Figure 21a). In this case, the exposed surfaces of sheet-like anatase TiO 2 are also mainly covered by -OH groups.…”

Section: Treatment-dependent Surface Featuresmentioning

confidence: 99%

“…[89] They suggested that the −Ti:F−H could greatly enhance O 2 adsorption and thus greatly promote the Reproduced with permission. [110] Copyright 2011, American Chemical Society. (b) Surface features schematic of TiO 2 and TiO 2 with F residues in atmosphere/water.…”

Section: Treatment-dependent Surface Featuresmentioning

confidence: 99%

See 2 more Smart Citations

Facet-dependent photocatalysis of nanosize semiconductive metal oxides and progress of their characterization

2018

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Semiconductive metal oxides are of great importance in environmental remediation and electronics because of their ability to generate charge carriers when excited with appropriate light energy. The electronic structure, light absorption and charge transport properties of the metal oxides have made possible their applications as photocatalysts. Recently, facet-engineering by morphology control has been intensively studied as an efficient approach to further enhance their photocatalytic performance. However, various processing steps and post-treatments used during the preparation of facet-engineered particles may generate different surface active sites which may affect their photocatalysis. Moreover, many traditional techniques (PL, EPR, XPS and Raman) used for materials characterization (oxygen vacancy, hydroxyl group, cation…etc.) are not truly surface specific but the analyses range from top few layers to bulk. Accordingly, they can only provide very limited information on the chemical states of the surface active features and distributions among facets, causing difficulty to unambiguously correlate facet-dependent results with activity. As a result, this always leads to different interpretations amongst researchers during the past decades. In this article, we will review on the controversies generated among researchers, when they correlated the performance of two most popular photocatalysts, ZnO and TiO 2 with their facet activities based on characterization from the traditional techniques. As there are shortcomings of these techniques in producing truly facet-dependent features, some results can be misleading and with no cross-literature comparison. This review is also focussed on the new capability of probe-molecule-assisted NMR which allows a genuine differentiation of surface active sites from various facets. This surface-fingerprint technique has been demonstrated to provide both qualitative (chemical shift) and quantitative (peak intensity) information on the concentration and distribution of truly surface features. In light of the new technique this article will revisit the facet-dependent photocatalytic properties and shed light on these issues.

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Section: Different Interpretations Amongst Researchersmentioning

confidence: 99%

Section: Treatment-dependent Surface Featuresmentioning

confidence: 99%

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Facet-dependent photocatalysis of nanosize semiconductive metal oxides and progress of their characterization

2018

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“…At 30 • C, the current density of silicone is proportional to the applied electric field, and the slope of J 1 is close to 1, which conforms to Ohm's law. At 30 • C, the slope of J 2 is greater than 2, indicating that the steady-state current density of silicone at this time transitions to the limited current stage by the trap-limited space charge [18]. At 50 to 90 • C, the increase in temperature enhanced the injection of charges from electrodes, which results in the formation of more carriers and increases the conductivity of the silicone.…”

Section: High Field Conductivity Of Silicone Encapsulating Materialsmentioning

confidence: 97%

Optimization Design of Packaging Insulation for Half-Bridge SiC MOSFET Power Module Based on Multi-Physics Simulation

Wang

Ding

et al. 2022

Energies

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With the development of power modules for high voltage, high temperature, and high power density, their size is becoming smaller, and the packaging insulation experiences higher electrical, thermal, and mechanical stress. Packaging insulation needs to meet the requirement that internal electric field, temperature, and mechanical stress should be as low as possible. Focusing on the coupling principles and optimization design among electrical, thermal, and mechanical stresses in the power module packaging insulation, a multi-objective optimization design method based on Spice circuit, finite element field numerical calculation, and multi-objective gray wolf optimizer (MOGWO) is proposed. The packaging insulation optimal design of a 1.2 kV SiC MOSFET half-bridge power module is presented. First, the high field conductivity characteristics of the substrate ceramic and encapsulation silicone of the packaging insulation material were tested at different temperatures and external field strengths, which provided the key insulation parameters for the calculation of electric field distribution. Secondly, according to the mutual coupling principles among electric–thermal–mechanical stress, the influence of packaging structure parameters on the electric field, temperature, and mechanical stress distribution of packaging insulation was studied by finite element calculation and combined with Spice circuit analysis. Finally, the MOGWO algorithm was used to optimize the electric field, temperature, and mechanical stress in the packaging insulation. The optimal structural parameters of the power module were used to fabricate the corresponding SiC MOSFET module. The fabricated module is compared with a commercial module by the double-pulse experiment and partial discharge experiment to verify the feasibility of the proposed design method.

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“…The concentration, particle size, and surface modification of nano‐fillers and the environmental humidity have a certain impact on the space charge distribution of the nanocomposites. [ 5‐11 ] Nelson et al tested the space charge distribution of crosslinked polyethylene (XLPE)/SiO 2 nanocomposites [ 10 ] and found that the addition of nano‐sized SiO 2 could inhibit the injection of space charges and the space charge injection threshold of the nanocomposites significantly increased. Kim et al investigated the space charge distributions of LDPE/graphene and LDPE/graphene oxide (GO).…”

Section: Introductionmentioning

confidence: 99%

Influence of polypyrrole nanospheres on the direct current dielectric properties of LDPE

Zhang

Ren

Cheng

et al. 2021

Polymer Engineering & Sci

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To study the effect of nano conducting materials on the direct current (DC) dielectric properties of low density polyethylene (LDPE), polypyrrole nanospheres are prepared by the soft template method and then melt‐blended with LDPE to obtain LDPE/polypyrrole nanocomposites. The micro‐structure, space charge distribution, thermally stimulated depolarization current, DC conductivity and DC breakdown strength of the nanocomposites are investigated. The results show there is interaction between polypyrrole nanospheres and LDPE, which will not affect the crystal structure of LDPE, but slightly increase the crystallinity of LDPE/polypyrrole nanocomposites. Polypyrrole nanospheres can introduce deep traps in LDPE to capture space charge carriers, which will suppress the accumulation of space charges in LDPE and reduce the DC conductivity. The DC breakdown strength of LDPE/polypyrrole nanocomposites is improved slightly by adding a small amount of polypyrrole nanospheres.

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Investigation of surface trap distribution in LDPE/SiO2 nanocomposite based on simultaneous observation of space charge and relaxation current

Cited by 20 publications

References 24 publications

Facet-dependent photocatalysis of nanosize semiconductive metal oxides and progress of their characterization

Facet-dependent photocatalysis of nanosize semiconductive metal oxides and progress of their characterization

Optimization Design of Packaging Insulation for Half-Bridge SiC MOSFET Power Module Based on Multi-Physics Simulation

Influence of polypyrrole nanospheres on the direct current dielectric properties of LDPE

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