No abstract

Stretchable electronics have important applications in health monitoring and integrated lab-on-a-chip devices. This paper discusses the performance of serpentine stretchable interconnects printed using self-reducing, silver reactive inks. It details process optimization, device fabrication, and device characterization, while demonstrating the potential applications for reactive inks and new design strategies in stretchable electronics. Devices were printed with an ethanol stabilized silver diamine reactive ink and cycled to stretch ratios of 140 and 160% over 1000 cycles with less than 2.5% variation in electrical resistance. Maximum deformation before failure was measured at 180% elongation. Additionally, interconnect deformation was compared to finite element analysis (FEA) simulations to show that FEA can be used to accurately model the deformation of low-strain printed interconnects. Overall, this paper demonstrates a simple and affordable route toward stretchable electrical interconnects.

No abstract

The ease of fabrication and wide application of printed microelectronics are driving advances in reactive inks. The long-term performance of structures printed using reactive ink is important for their application in microelectronics. In this study, silver lines are printed with low-temperature, self-reducing, silver-diamine based ink. The electromigration failure of the printed silver is first studied using Black's equation. However, due to the porous nature of the printed Ag line, Black's equation is not the best fit for predicting the lifetime, this is because Black's equation does not take into account morphology-induced current crowding. We find that the resistivity of the printed Ag lines can be described (as a function of void fraction) by percolation theory. In addition, we also demonstrate that the failure lifetimes of the printed Ag can be predicted quite well by a percolative model of failure.

Phone: þ480 965 4912Reactive metal inks have the potential to replace particlebased inks for printed metals and electrodes. Recent advances in self-reducing silver inks have dropped the reduction temperature from >180 8C down to room temperature. However, most reactive inks are printed at room temperature and sintered at an elevated temperature to achieve good electrical resistivity. In this work, we demonstrate that low electrical resistivity (1.8 mVcm) can be achieved by adjusting solvent selection and printing at slightly elevated temperatures. This work examines the impact of solvent type and substrate temperature on the resulting morphology and electrical properties of silver films printed with a selfreducing silver-diamine ink. We show that morphology, porosity, and media resistivity can be controlled to produce a dense film without sintering. The porosity was adjusted from 93% down to 50% and the media resistivity two orders of magnitude from 180 mVcm down to 1.8 mVcm. The lowest media resistivity was found for a 10:1-EtOH:Ag ink printed at 66 8C. Overall, this process demonstrates that highly conductive silver films can be printed at low temperatures with broad control over morphology and without post-print annealing.Reactive inks print silver with controllable porosity.