Synthesis and self-assembly of large-area Cu nanosheets and their application as an aqueous conductive ink on flexible electronics.

Large-area Cu nanosheets are synthesized by a strategy of Cu nanocrystal self-assembly, and then aqueous conductive Cu nanosheet ink is successfully prepared for direct writing on the conductive circuits of flexible electronics. The Cu nanocrystals, as building blocks, self-assemble along the [111] direction and grow into large-area nanosheets approximately 30-100 μm in diameter and a few hundred nanometers in thickness. The laminar stackable patterns of the Cu nanosheet circuits increase the contact area of the Cu nanosheets and improve the stability of the conductor under stress, the result being that the Cu nanosheet circuits display excellent conductive performance during repeated folding and unfolding. Moreover, heterostructures of Ag nanoparticle-coated Cu nanosheets are created to improve the thermal stability of the nanosheet circuits at high temperatures.