Liquid metal printing for atomically thin metal-based materials and devices: toward atomic-level manufacturing

Atomic-level manufacturing represents the ultimate frontier in materials science, promising unprecedented control over the composition and structure of matter. However, conventional fabrication techniques often face limitations in terms of scalability, energy efficiency, and applicability to non-layered materials. Liquid metal (LM) printing has recently emerged as a disruptive alternative, leveraging the unique physicochemical properties of liquid metals, including high fluidity, self-limiting surface oxidation, and compositional tunability, to synthesize and transfer atomically thin films under ambient conditions. This review provides a comprehensive overview of LM printing for the fabrication of two-dimensional (2D) metal-based materials and devices. We begin by elucidating the fundamental principles of atomic-level manufacturing and the distinctive advantages of liquid metals. We then systematically detail a diverse toolkit of LM printing techniques, including gas injection, laser-assisted, spin-coating, scraping, roller-based, squeeze-printing, and direct touch methods. The synthesis of a broad library of atomically thin materials, encompassing oxides, sulfides, nitrides, and phosphates derived from Ga, In, Sn, Bi, Zn, and their multi-component alloys, is thoroughly reviewed. Furthermore, we explore the integration of these 2D materials into high-performance devices such as transistors, photodetectors, sensors, memristors, and neuromorphic electronics. Finally, we discuss the existing challenges and future outlooks for this burgeoning field, highlighting pathways toward autonomous, scalable, and truly atomic-level manufacturing paradigms.