All Laser Micro-fabrication of Stretchable Sensors

With the development of the Internet of Things (IoT), stretchable sensors with high sensitivity and good conformality have attracted tremendous interest. In recent years, the laser micro-fabrication (LMF) method has shown the potential application in fabricating various stretchable sensors. Nevertheless, how to modulate the properties of the sensing element (SE) and conductive interconnect structure (CIS) in the LMF process to meet the application requirements for stretchable sensors is still a challenge for LMF. This study proposed an all-LMF technology to fabricate stretchable sensors. Laser induced reduction and laser induced ablation (LIA) are used to prepare serpentine Cu-CIS with a high conductivity of 123 μΩ·cm, minimized response to deformation (sensitivity<1x10 ^-3 ), and a high stability at strain up to 150%. Laser induced pyrolysis and LIA is used to synthesize graphene-SE with bio-inspired microcracks, demonstrating a ~210 times increment in sensitivity than the one without microcracks. The conjunction of the CIS and SE is formed by Cu nanoparticle and graphene composites, exhibiting insensitivity (sensitivity<0.42) to mechanical deformations. Representative applications fully demonstrate that LMF devices can be customized to the size and structure required, with stability and economy.