Transparent and flexible electromagnetic interference shielding thin film based on sulfurized copper iodide

A transparent and flexible electromagnetic interference (EMI) shielding thin film is fabricated through a two-step process involving magnetron sputtering of copper iodide (CuI), followed by sulfurization. This Cu–I–S compound effectively combines the high optical transparency of the CuI matrix with the enhanced electrical conductivity imparted by sulfur incorporation. The optical and electrical properties of the Cu–I–S thin film can be systematically tuned by modulating the I/S ratio. Notably, the films exhibit exceptional mechanical stability, with less than 5% variation in conductivity after 5000 bending cycles at a curvature radius of 8 mm. These thin films achieve an optimal electromagnetic shielding effectiveness of ∼30 dB at the X-band (8–12 GHz). These findings reveal the great potential of CuI-based materials in various optoelectronic and flexible device applications.