Synthesis of Vertical Graphene Nanowalls on Substrates by PECVD as Effective EMI Shielding Materials
Zehui Wang, Honglie Shen, Kewen Luo, Weibiao Mao, Yajun Xu, Jiawei Ge, Junkui Zhu, Yufang Li, Tianru Wu
Abstract
Electromagnetic interference (EMI) shielding materials with low thickness and improved EMI shielding performance are highly required. Herein, by utilizing the plasma-enhanced chemical vapor deposition (PECVD) method with the optimized source power of the plasma generator, vertical graphene nanowalls (VGNs) with a relatively rapid growth rate of ∼5 μm·h–1 were prepared on substrates. The porous conductive VGNs exhibited preferable EMI shielding performance. In a frequency range of 8.2–12.4 GHz, the EMI shielding effectiveness (SE) value of VGNs with a thickness of 47.5 μm could reach 26.2 dB. In addition, VGNs with controllable thickness were also synthesized on Cu foam substrates. The combination of VGNs and Cu foam significantly improved the porosity and interfacial coupling effect of the composites. By growing VGNs with a thickness of ∼20 μm on the Cu foam, their absorption efficiency got largely enhanced by 13.8 dB (32.2%) compared with the pristine Cu foam. Subsequently, the total EMI SE of the VGNs/Cu foam composite films got enhanced by 13.5 dB (20.8%) compared with the pristine Cu foam. The VGNs and their composites with preferable EMI shielding performance establish potential for practical applications in EMI shielding.