A Strategy toward Realizing Narrow Line with High Electrical Conductivity by Electrohydrodynamic Printing

Over the past few decades, electrohydrodynamic (EHD) printing has proved to be an environmentally friendly, cost-effective and powerful tool in manufacturing electronic devices with a wire width of less than 50 μm. In particular, EHD printing is highly valued for the printing of ultrafine wire-width silver electrodes, which is important in manufacturing large-area, high-resolution micron-scale or even nanoscale structures. In this paper, we compare two methods of surface modification of glass substrate: UV treatment and oxygen plasma treatment. We found that oxygen plasma was better than UV treatment in terms of wettability and uniformity. Secondly, we optimized the annealing temperature parameter, and found that the conductivity of the electrode was the highest at 200 °C due to the smoothing silver electrode and the oxidation-free internal microstructure. Thirdly, we used EHD printing to fabricate silver electrodes on the glass substrate. Due to the decrease of conductivity as a result of the skin effect and the decrease of silver content, we found that driving voltage dropped, line width decreased, and the conductivity of silver line decreased. After the optimization of the EHD printing process, Ag electrode line width and conductivity reached 19.42 ± 0.24 μm and 6.01 × 10⁶ S/m, demonstrating the potential of electro-hydraulic printing in the manufacturing of flexible, wearable, high-density, low-power-consumption electronics.