Synergistic Photonic Sintering of Robust Cu@AgNWs for Environmentally Stable Electromagnetic Interference Shielding...

Copper nanowires (CuNWs) present a promising low-cost alternative to indium tin oxide for next-generation flexible electronics. However, their widespread use is hindered by their natural tendency to oxidize and the difficulty of establishing effective interwire connections on thermally sensitive substrates. Here, we introduce durable, oxidation-resistant transparent conductive films (FTCFs) made from Cu@Ag core-shell nanowires, produced through a pulsed photonic sintering process. Combined multiphysics simulations and systematic experiments reveal that the innovation of this work lies in a synergistic photonic-sintering mechanism rather than in the separate use of Cu@AgNWs, transparent heating, or electromagnetic interference (EMI) shielding. During the short-pulse treatment, localized photothermal activation promotes nanowire junction welding, while transient softening of the PI surface enables partial nanowire embedding and interfacial anchoring. This coupled mechanism integrates Ag-shell-enabled oxidation resistance, low-resistance welded junctions, substrate-assisted mechanical stability, transparent EMI shielding, and rapid low-voltage electrothermal response in one Cu-based flexible transparent conductive film. This architecture simultaneously provides excellent electrical conductivity and strong interfacial adhesion without damaging the structure. As a result, these optimized FTCFs achieve a competitive sheet resistance of 16.9 Ω/sq at 81.6% transmittance and demonstrate remarkable stability under mechanical stress and environmental conditions. Showing versatile multifunctionality, the films exhibit effective X-band EMI shielding performance (up to 39 dB) and function as transparent heaters with rapid low-voltage electrothermal response, reaching a temperature increase of more than 70 °C at 3 V and showing fast switching-induced temperature variation within the 1 s acquisition interval. This work offers a scalable, mechanism-based approach for producing high-performance Cu-based FTCFs, emphasizing their great potential in advanced high-frequency shielding and wearable thermal management.