Fast single-crystallization of Cu foils Facilitated by graphene growth

The production of large-area single-crystal metal foils such as Cu and Ni has recently gained momentum through thermally annealing of commercially available polycrystalline foils. Surface energy plays a pivotal role for grain growth, but is usually insufficient, particularly for adjacent grains with similar surface orientations, causing prolonged annealing time and reproducibility issues. Our method accelerates Cu foil single-crystallization through graphene growth, where graphene coverage on Cu modulates surface energy, enhancing driving forces and accelerating grain growth. This is a critical breakthrough in overcoming the traditional grain growth limitations. We successfully prepare decimeter-sized single-crystal Cu (111) foils with high efficiency and reproducibility and use it for single-crystal graphene growth. Our method paves the way for the scalable production of large-area single-crystal Cu foils, with potential applications extending to other metals, contributing to the ongoing efforts to overcome the challenges associated with traditional single-crystal production methods.