Preparation and application of gallium-based conductive materials in the very recent years

Gallium and its alloys are a group of metallic materials with low-melting points at or around room temperature. Apart from the good electrical conductivity, the unique liquid state endows those metals with excellent compliance and self-healing capacity, which present great value in the development of flexible and stretchable electronics. Constrained by the high surface tension and low viscosity, however, liquid metals cannot be applied to some common microelectronics manufacturing technologies such as micro-electro mechanics in the preceding years, which impedes their mass production in electronic devices. To address these issues and broaden the applications of liquid metals in electronics devices, numerous efforts have been taken and great progress has been made especially in the very recent years. This review summaries the recent development of liquid metal-based conductive materials from the aspects of preparation or modification methods and their accommodative fabrication techniques in flexible electronic applications. Further outlook including expectations and challenges of liquid metal-based conductive materials are also presented.