Laser-Induced High-Throughput Printing of Liquid Metal

Liquid metals, such as gallium-based alloys, have gained significant attention as ideal materials for flexible electronic devices due to their nontoxicity, harmlessness at room temperature, excellent electrical conductivity, and superior flexibility, ensuring exceptional resistance to bending and stretching. Although various patterning methods for liquid metals have been developed, they often suffer from long preparation cycles and complex procedures. This paper presents a straightforward and efficient method for liquid metal patterning. It harnesses nanosecond laser irradiation on the liquid metal surface to generate microexplosion-induced high pressure, enabling the ejection of liquid metal droplets. This approach allows for high-frequency inkjet printing of liquid metals, even in the presence of oxide films. By employing a galvanometric scanning system, the nanosecond laser is directed toward an array of orifices, enabling liquid metal droplet ejection frequencies exceeding kilohertz. Furthermore, this paper delves into the mechanism of laser-induced liquid metal droplet ejection, investigates the influence of different laser parameters and orifice geometries on the characteristics of liquid metal ejection, and establishes a theoretical and technical foundation for achieving precise and efficient patterning of liquid metals.