High-Precision Printing\nSandwich Flexible Transparent\nSilver Mesh for Tunable Electromagnetic Interference Shielding Visualization\nWindows

Flexible transparent conductive films (FTCFs) with electromagnetic\ninterference (EMI) shielding performance are increasingly crucial\nas visualization windows in optoelectronic devices due to their capabilities\nto block electromagnetic radiation (EMR) generated during operation.\nMetal mesh-based FTCFs have emerged as a promising representative\nin which EMI shielding effectiveness (SE) can be enhanced by increasing\nthe line width, reducing the line spacing, or increasing mesh thickness.\nHowever, these conventional approaches decrease optical transmittance\nor increase material consumption, thus compromising the optical performance\nand economic viability. Hence, a significant challenge still remains\nin the realm of metal mesh-based FTCFs to enhance EMI SE while maintaining\ntheir original optical transmittance and equivalent material usage.\nHerein, we propose an innovative symmetric structural optimization\nstrategy to create silver mesh-based sandwich-FTCFs with arbitrary\ncustomized sizes through high-precision extrusion printing technology\nfor tunable EMI shielding performance. The meticulous adjustment\nof <i>xy</i>-axis offsets and printing starting point ensures\nperfect alignment of the silver mesh on both sides of the transparent\nsubstrate. This approach yields sandwich-FTCFs with optical transmittance\nequivalent to single-layer-FTCFs under identical parameters while\nsimultaneously achieving up to 40% enhanced EMI SE. This improvement\nstems from the synergistic effect of multiple internal reflections\nand wave interference between the symmetric silver meshes. The excellent\nshielding performance of sandwich-FTCFs is evidenced through effectively\nblocking electromagnetic waves from common devices such as mobile\nphones, Bluetooth earphones, and smartwatches. Our work represents\na significant advancement in balancing optical transmittance, EMI\nSE, and material efficiency in high-performance and cost-effective\nFTCFs.