Additive Manufacturing of Metal Nanowire via Focus‐Assisted Electrohydrodynamic Printing With High Stability

ABSTRACT Flexible electronics, including biosensors and new displays, are revolutionary devices and are facing a major manufacturing hurdle. Metal nanowire is the foundation of flexible electronics. It requires a process that is high precision (≤ 500 nm), compatible with diverse functional inks (viscosity in the range of 5–1,0000 mPa s) and efficient for large‐scale production. Traditional techniques typically satisfy only one or two of the mentioned three aspects, making a transformative technology desirable. Electrohydrodynamic (EHD) printing emerges as a highly promising solution to this triple challenge. Its unique ‘pull’ principle allows it to print nanoscale features, handle a wide range of ink materials and achieve high throughput with multinozzle systems. This effectively integrates the key advantages needed for advanced flexible electronics manufacturing. However, to fully realise its potential, several challenges must be addressed. A deeper theoretical understanding of the complex interaction between the metal particle ink properties and the electric field is needed to guide ink formulation. Furthermore, developing precise control strategies for voltage and flow rate is crucial to ensure stable and reliable printing performance. The solutions for the problem of nozzle blockage also need to be found. Moreover, the proposal of post‐treatment of deposited metal particle ink line is needed for obtaining excellent nanoscale metal lines. The stability of printing should be improved using focus‐assisted EHD (FA‐EHD) printing. FA‐EHD can stabilise EHD printing from the effect of 0th/1st/2nd‐order instability. Overcoming these challenges will make EHD printing a key manufacturing technology that drives the evolution of next‐generation, high‐performance flexible electronics.