Liquid Metal as Electrical Interface Material with Temporal Stability and Stretch Tolerance

Electrical interface material (EIM) is an important component to develop stretchable electronics. Currently available EIMs suffer from the trade-off between low value and stretch tolerance of contact resistance. To overcome this challenge, we demonstrated the use of liquid metal (LM) as an EIM between solid metal (SM) pads for stretchable electronic devices. With LM, we achieved low contact resistance with temporal stability and stretch tolerance. Our study suggested that the contact resistance between an LM and an SM decreases over time due to alloying, and the contact resistance was reduced to 18.6% in 103 days by ensuring the electrical connection under vacuum during the fabrication. Furthermore, the use of the LM as an EIM enabled maintaining the change in contact resistance below 9% during 100% stretching deformation repeated 100 times. These results suggest that LM can be used as an EIM with temporal stability and stretch tolerance.