Low-temperature sintering of silver patterns on polyimide substrate printed with particle-free ink.

In this study, a transparent particle-free reactive silver ink was used to fabricate conductive patterns on a flexible substrate. Thermal annealing and plasma irradiation at low temperature were utilized to improve the conductivity of the as-printed patterns. The effects of sintering process parameters on the microstructure and resistivity of the patterns were investigated. Under the optimized processing conditions, the resistivity of the pattern reached 1.2 × 10 -7 Ω · m by thermal sintering, while it was 8 × 10 -8 Ω · m after plasma sintering. Combined with these two sintering techniques, the resistivity was reduced to 6 × 10-8 Ω · m, close to that of bulk silver. This work provides an alternative solution for the fabrication of highly conductive feature patterns on common flexible substrates.