▎ 摘　　要

With the rapid development of wireless electronic facilities, the demand for high-performance electromagnetic shielding films has swiftly increased. Graphene is a desirable electromagnetic interference (EMI) shielding material due to its excellent electrical conductivity and light transmittance. Previous studies mostly focus on polycrystalline graphene sheets and the performances are far below the theoretical value due to poor crystal quality. In this paper, the authors demonstrate a flexible ultrathin transparent EMI film based on large-area single crystal graphene (SCG), which is grown on single crystalline Cu substrates by chemical vapor deposition. Their flexible transparent EMI films show ultrahigh electromagnetic shielding effectiveness (SE). This can be attributed to the high crystalline quality and outstanding electronic conductivity of the as-used graphene film. The electromagnetic shielding effectiveness of the SCG/MgF/SCG sandwiched structure can reach over 8.10 dB, and the normalized electromagnetic SE is up to 5.5 x 10(7) dB cm(2) g(-1), much higher than the recorded materials. Moreover, their large area single-crystal graphene EMI films exhibit a high and broad wavelength transmittance from visible to infrared range (e.g., infrared transmittance of 94% at 5000 nm). A flexible EMI lid of SCG has been investigated for effectively blocking WIFI signals and phone radiation.