Key Laboratory of Smart Grid of Education Ministry, School of Electrical and Information Engineering, Tianjin University, Tianjin, 300072, China.
Sci Rep. 2017 Jun 21;7(1):4015. doi: 10.1038/s41598-017-04196-5.
The role of trap characteristics in modulating charge transport properties is attracting much attentions in electrical and electronic engineering, which has an important effect on the electrical properties of dielectrics. This paper focuses on the electrical properties of Low-density Polyethylene (LDPE)/graphene nanocomposites (NCs), as well as the corresponding trap level characteristics. The dc conductivity, breakdown strength and space charge behaviors of NCs with the filler content of 0 wt%, 0.005 wt%, 0.01 wt%, 0.1 wt% and 0.5 wt% are studied, and their trap level distributions are characterized by isothermal discharge current (IDC) tests. The experimental results show that the 0.005 wt% LDPE/graphene NCs have a lower dc conductivity, a higher breakdown strength and a much smaller amount of space charge accumulation than the neat LDPE. It is indicated that the graphene addition with a filler content of 0.005 wt% introduces large quantities of deep carrier traps that reduce charge carrier mobility and result in the homocharge accumulation near the electrodes. The deep trap modulated charge carrier transport attributes to reduce the dc conductivity, suppress the injection of space charges into polymer bulks and enhance the breakdown strength, which is of great significance in improving electrical properties of polymer dielectrics.
陷阱特性在调制电荷输运性质方面的作用在电气工程中引起了广泛关注，这对电介质的电学性质有重要影响。本文主要研究了填充量为 0wt%、0.005wt%、0.01wt%、0.1wt%和 0.5wt%的石墨烯纳米复合材料（NCs）的低密聚乙烯（LDPE）的电学性能及相应的陷阱能级特性。通过测试直流电导、击穿强度和空间电荷行为，研究了 NCs 的陷阱能级分布。实验结果表明，与纯 LDPE 相比，0.005wt%LDPE/石墨烯 NCs 的直流电导较低，击穿强度较高，空间电荷积累量较小。这表明，添加含量为 0.005wt%的石墨烯会引入大量深载流子陷阱，降低载流子迁移率，导致电极附近的同荷积累。深陷阱调制载流子输运特性降低了直流电导率，抑制了空间电荷注入聚合物基体，并提高了击穿强度，这对改善聚合物电介质的电学性能具有重要意义。
