A review of liquid metal-based flexible electronics achieved by ultrafast lasers

Gallium and its alloys are room temperature liquid metals, which exhibit both the fluidity of liquid and the conductivity of metal. Recently, Gallium-based liquid metals have aroused great attention and played a crucial role in flexible sensors, self-healing circuits, stretchable electrodes, and soft robots. Within these fields, developing advanced printing technology was the key to obtain liquid metal-based electronic devices. Ultrafast laser microfabrication has the characteristics of high precision and low thermal effect. This technology has been successfully applied to prepare various liquid metal patterns and contributed for the development of flexible electronics. In this review, the recent advances of gallium-based flexible electronics by ultrafast lasers are systematically summarized. We mainly focus on the physical and chemical properties of liquid metals, laser-induced liquid metal printing methods, and their typical applications in flexible electronics. Finally, the challenges and personal perspectives of liquid metal-based flexible electronics are briefly discussed.