Rational Nanoarchitecturing of Coinage Metals via Kinetically Controlled Mass-Limited Reaction with EGaIn Nanoparticles

Metallic nanoarchitectures over a large area are attractive for sensors, electronics, energy storage, and catalysis. However, the scalable synthesis of metallic nanoarchitectures with rational control is still challenging. In this study, facile large-scale nanoarchitecturing of coinage metals (Cu, Ag, and Au) is achieved by kinetically controlled alloying and dealloying reactions between eutectic gallium-indium nanoparticles (EGaIn NPs) and coinage metals with HCl treatment. Unlike the reaction of coinage metal films with EGaIn bulk, the two-dimensional coinage metal thin films with EGaIn NP coating and HCl treatment enable the formation of kinetically stable intermetallic phases with minimal volume expansion and facile fabrication of rationally designed porous films. Moreover, whereas bulk metals form porous and rough surfaces, one-dimensional coinage metal nanowires (NWs) undergo chemical welding at room temperature while preserving their NW morphology, providing resilience against volume expansion. The welded Ag NWs are used to fabricate transparent conductive electrodes with a record-high figure of merit of 795.2 and a stretchable electrode with a marginal resistance increase of 25% at 10% strain. Finally, combining welded and unwelded Ag NWs, an all-Ag NW-based strain sensor achieves a gauge factor of 3.67 at 30% strain, balancing sensitivity, and conductivity. The kinetically controlled intermetallic reactions of EGaIn on the nanoscale could enable the rational design and fabrication of next-generation metallic nanoarchitectures for diverse technological applications.