Direct printing of performance tunable strain sensor via nanoparticle laser patterning process

Flexible electronics are attractive because of flexibility and portability. The circuits are printed on flexible substrates, which are delicate and heat-sensitive. Traditional photolithography, which uses high temperatures and corrosive chemicals, easily causes damages in flexible substrates. Here, we develop a low-cost nanoparticle based laser patterning process for fabrication of flexible electronics. Nanoparticles are sintered using a low-power laser as they are selectively deposited. Copper and silver particles were successfully deposited on paper and polyethylene terephthalate substrates. The effects of process parameters on deposition performance were studied to understand the process-structure–property relationship. The thermal effects of the laser on film morphology were observed. The sensitivities of the electrical properties with respect to the porosities at different laser power densities were analysed. With different laser energy levels, the process allows for selective deposition, properties control of printed patterns, and flexible substrate cutting. The fabrications of strain sensor and kirigami electronics were demonstrated.