Li Hongfei, Qu Zhaoming, Chen Yazhou, Zhou Linsen, Wang Yan
National Key Laboratory on Electromagnetic Environment Effects, Army Engineering University, Shijiazhuang 050003, China.
Institute of Materials, China Academy of Engineering Physics, Mianyang 621907, China.
Polymers (Basel). 2022 Jul 21;14(14):2949. doi: 10.3390/polym14142949.
Polymer nanocomposites can serve as promising electrostatic shielding materials; however, the underlying physical mechanisms governing the carrier transport properties between nanofillers and polymers remain unclear. Herein, the structural and electronic properties of two polyethylene/graphene (PE/G) interfaces, i.e., type-H and type-A, have been systematically investigated under different electric fields using first principle calculations. The results testify that the bandgaps of 128.6 and 67.8 meV are opened at the Dirac point for type-H and type-A PE/G interfaces, respectively, accompanied by an electron-rich area around the graphene layer, and a hole-rich area around the PE layer. Moreover, the Fermi level shifts towards the valence band maximum (VBM) of the PE layer, forming a p-type Schottky contact at the interface. Upon application of an electric field perpendicular to the PE/G interface, the Schottky contact can be transformed into an Ohmic contact via the tuning of the Schottky barrier height (SBH) of the PE/G interface. Compared with the A-type PE/G interfaces, the H-type requires a lower electric field to induce an Ohmic contact. All these results can provide deeper insights into the conduction mechanism of graphene-based polymer composites as field-shielding materials.
聚合物纳米复合材料可作为有前景的静电屏蔽材料；然而，纳米填料与聚合物之间载流子传输特性的潜在物理机制仍不清楚。在此，利用第一性原理计算，系统研究了两种聚乙烯/石墨烯（PE/G）界面（即H型和A型）在不同电场下的结构和电子性质。结果表明，对于H型和A型PE/G界面，在狄拉克点分别打开了128.6和67.8 meV的带隙，同时在石墨烯层周围有富电子区域，在PE层周围有富空穴区域。此外，费米能级向PE层的价带最大值（VBM）移动，在界面处形成p型肖特基接触。当施加垂直于PE/G界面的电场时，通过调节PE/G界面的肖特基势垒高度（SBH），肖特基接触可转变为欧姆接触。与A型PE/G界面相比，H型需要更低的电场来诱导欧姆接触。所有这些结果可为基于石墨烯的聚合物复合材料作为场屏蔽材料的传导机制提供更深入的见解。
