Current Carrying Capacity of Inkjet-Printed Nano-Silver Interconnects on Mesoporous PET Substrate

Conductors are a basic component in any flexible hybrid electronic device. Their electromechanical reliability has been studied, yet very few studies report their thermoelectric behavior. We report the current carrying capacity of an inkjet-printed nano-silver interconnects on mesoporous PET substrate. For this study, the printed interconnects are approximately 100 μm wide, with two different thicknesses: single layer (~650 nm thick) and double layer (~1 μm thick). Samples were sintered with different parameters of oven and laser sintering. The effect of printing and curing parameters on the trace current-carrying capability is evaluated with and without the presence of an encapsulation layer. At the current sweep range of 0.005-0.08A for single layer traces and 0.005-0.17A for double layer traces, results show that the trace resistance slightly increases and then decreases to a minimal value smaller than the initial resistance before dramatically increases indicating substrate damage. The double-layer traces withstand higher current and reach higher temperature than the substrate glass transition point. The oven sintered traces have higher initial resistance than laser sintered samples reflecting the difference in the percentage of solvent content and the microstructure. A drastic decrease in resistance is noticed at low current for the oven sintered samples, but at higher current, both oven and laser sintered traces showed similar behavior. The printed encapsulation layer did not significantly impact the trace behavior. A thermoelectric simulation of the trace joule heating was generated in order to quantify the thermal energy transmitted to the surrounding environment and capture the temperature of the trace surface. The model was compared to the experimental results and showed a good correlation.