Electrical performance and reliability assessment of silver inkjet printed circuits on flexible substrates

Inkjet printing has proven to be a promising alternative method in the fabrication of printed electronics, besides screen printing and photolithography etching. In this work, we characterize the electrical performance of inkjet printed circuits on flexible PET and glossy photo paper. The electrical circuits were printed using a commercial Epson L310 piezoelectric printer, and the NB series silver ink and chemical-sintering PET substrate from Mitsubishi Paper Mills. This method allows rapid prototyping of electronic circuits (~ 30 min design, ~ 5 s fabrication) and quick iteration of prototypes. The system has a resolution of 250 µm electrodes and 300 µm electrical gaps, and on average, 1.5 ± 0.2 µm in thickness. The effect of printing on different substrates, geometry and overprinting on sheet resistance was also studied. It was found that double printing produced better electrodes with lower resistances. A stable conducting circuit has a sheet resistivity of