Toward 3D‐Printed Electronics: Inkjet‐Printed Vertical Metal Wire Interconnects and Screen‐Printed Batteries

Inkjet and screen printing technologies are well known in the graphic arts industry for the reproduction of texts, images, and graphics. During the last decades, these printing technologies have been attracting increasing interest for the deposition of functional materials, e.g., in the field of printed electronics and for biological applications. However, their usage is mainly limited to 2D applications, i.e., rather flat deposits ranging from nanometers to several tens of micrometers in thickness. For 3D applications, sophisticated additive manufacturing technologies are developed to manufacture structures with high shape complexities. Herein, the potential of standard inkjet and screen printing technology as tools for the development of functional 3D objects is demonstrated. 3D functional structures printed by inkjet and screen printing technology combining conductive and nonconductive materials to a multi‐material structure are shown. A metal nanoparticle ink formulation is applied to inkjet‐print conductive metal pillars with a high aspect ratio (in the range of 50) used as vertical interconnects. The interconnects are encapsulated with an inkjet‐printed polymeric ink formulation and finally used as conductive tracks to light up a solid‐state light‐emitting diode (LED). Screen printing is applied to print primary batteries used as the power source for the LED.