Cu-Ag and Ni-Ag meshes based on cracked template as efficient transparent electromagnetic shielding coating with excellent mechanical performance
Nowadays, the technical advances call for efficient electromagnetic interference (EMI) shielding of transparent devices which may be subject to data theft. We developed Cu–Ag and Ni–Ag meshes on flexible PET substrate for highly efficiency transparent EMI shielding coating. Cu–Ag and Ni–Ag meshes obtained with galvanic deposition of copper and nickel on thin Ag seed mesh which was made by cracked template method. Coefficients S11, S21 and shielding efficiency (SE) were measured for Cu–Ag and Ni–Ag meshes in X-band (8–12 GHz) and K-band (18–26.5 GHz). 90 s copper deposition increase SE from 23.2 to 43.7 dB at 8 GHz with a transparency of 82.2% and a sheet resistance of 0.25 Ω/sq. The achieved maximum SE was 47.6 dB for Cu–Ag mesh with 67.8% transparency and 41.1 dB for Ni–Ag mesh with 77.8% transparency. Cu–Ag and Ni–Ag meshes have high bending and long-term stability. Minimum bend radius is lower than 100 µm. This effect allows to produce different forms of transparent shielding objects, for example, origami method. Our coatings are the leading among all literary solutions in three-dimensional coordinates: of sheet resistance–optical transmittance–cost of produced.