Abstract
Electric conductive materials is one of the most promising materials for electromagnetic interference (EMI) shielding. Generally, the EMI shielding efficiency (EMI SE) increases with electric conductivity. This study demonstrated a method to produce a film coated with silver nanowire/reduced graphene oxide (AgNW/rGO), and the film was then hot-pressed with silver grid to fabricate a composite film with excellent efficiency of EMI shielding. In order to reduce the electric resistance of the film coated with AgNWs, graphene oxides were introduced to the AgNW solution. During the reaction, graphene was reduced from GO and wrapped AgNWs, as a result, enhance electric property of the AgNWs. The AgNW/rGO film with low sheet resistance of 56.50 ± 1.52 ohm/sq, extremely high transmittance of 92.62 % and moderate EMI SE of 10.24 dB at a frequency of 1.8 GHz was attained. The film with 1.0 mm spacing grid possessed low sheet resistance of 18.60 ± 0.76 ohm/sq and high EMI SE of 28.88 dB, however, lower transmittance of 82.78 % was also detected at the frequency of 1.8 GHz. After hot-pressing, AgNW/rGO and 1.0 mm spacing grid showed very low sheet resistance of 1.60 ± 0.14 ohm/sq and a transmittance of 74.40 % with a very high EMI SE of 42.94 dB at the frequency of 1.8 GHz. The improvement was due to AgNWs played a role of creating conductive path at the voids of gird and thus reduced the resistance. We also used the HFSS program to conduct EMI shielding simulation for silver grid. We provided a theoretical analysis for better understanding the influences of spacing and line width of the grid on EMI SE.