Investigation on graphene/Ag nano-particles composite ink for flexible electronics

In this study, hybrid conductive ink composed of graphene (0.5wt%) and Ag nanoparticles (40wt%) for inkjet printing is presented by mechanical mixing process. Then, hot-press sintering process has applied to achieve the final interconnect structure after printing on the paper substrate. We can achieve reasonably low electrical resistivity under low sintering temperature (120°C). Specifically, an excellent resistivity of 2.95×10^-8Ω m, which is 1.9 times the value for bulk silver, was achieved in the test (120°C, 16min, 6MPa). The effects of different sintering time have been investigated. As the figure indicated, the electrical resistivity decreases as the sintering time increases. Mechanical properties have also been tested. The resistance values of the printed tracks only change slightly after thousands of bending cycles or stretching. More importantly, compared to pure silver nanoparticles conductive ink, hybrid conductive ink has more advantages on the electrical conductivity and flexibility to fabricate flexible electronics. The discussion of these effects will be further investigated based on microstructure analysis in the coming full paper submission.