Photo-patternable, large-area semi-solid-state liquid metal film coated via suspension shearing for soft electronics

Abstract

Liquid metal (LM) is considered one of the most promising conducting materials for soft electronics due to its unique combination of metal-level high conductivity with exceptional deformability and stretchability. However, its practical applicability has thus far been limited due to the challenges of generating chemically and mechanically stable films over a large area and the need for non-standard fabrication approaches. Here, we report materials and manufacturing methods that enable the multiscale patterning (from microns to centimeters) and multilayer integration of ‘semi-solid-state liquid metal (SeLM)’ thin-film with the conventional cleanroom process. In this work, suspension shearing of a polyelectrolyte-attached LM particle ink is used to generate SeLM films. The stabilized LM particles formed close-packed assembly without particle rupture when coated under the evaporative regime. This is essential in enabling a subsequent photolithographic lift-off process at a wafer-scale to produce high-resolution features (~10 μm) of varying thicknesses on various substrates. Demonstrations of multilayered high-resolution tactile sensing systems, large-area stretchable display, and deformable skin-interfaced electronics validate the simplicity, versatility, and reliability of this manufacturing strategy, suggesting broad utility in the development of advanced soft electronics.