Transparent Ultrathin Doped Silver Film for Broadband Electromagnetic Interference Shielding

A high-performance electromagnetic interference (EMI) shielding film based on a dielectric-metal-dielectric structure incorporating ultrathin Silver is proposed. The ITO/Cu-doped Ag/ITO (ICAI) film was deposited on flexible Polyethylene terephthalate (PET) substrates at room temperature. The ICAI film transmits $\sim 96.5$% visible light (reference to PET substrate) over spectral range 400 – 700 nm. The film stack shows an excellent average EMI shielding effectiveness (SE) of $\sim 26$ dB, exhibiting a broadband shielding with the bandwidth of 32 GHz, which covers the entire X, Ku, Ka, and K bands. The dielectric-metal-dielectric design greatly relieves the trade-off between optical transmittance and EMI shielding performances. EMI SE exceeds 30 dB can be simply obtained by stacking two layers of ICAI films together. In addition, the flexible ICAI film demonstrates a stable EMI shielding performance under mechanical deformation. The outstanding optical, broadband EMI shielding and mechanical properties of ICAI film render it promising for various applications in healthcare, electronic safety, and fast-growing next-generation flexible electronics, such as roll-up displays and wearable devices.