Scientists have developed a process to 3D-print transparent and flexible electronic circuits, paving the way for improved wearable devices in the future. The electronics consists of a mesh of silver nanowires that can be printed in suspension and embedded in various flexible and transparent plastics, according to the researchers from the University of Hamburg and Deutsches Elektronen-Synchrotron (DESY) in Germany.
This technology can enable new applications such as printable light-emitting diodes, solar cells or tools with integrated circuits. The researchers are demonstrating the potential of their process with a flexible capacitor, among other things.
"The aim of this study was to functionalise 3D-printable polymers for different applications," said Michael Rubhausen from the Center for Free-Electron Laser Science (CFEL), a cooperation between DESY, the University of Hamburg and the Max Planck Society.
"With our novel approach, we want to integrate electronics into existing structural units and improve components in terms of space and weight," Rubhausen said in a statement. "At the heart of the technology are silver nanowires, which form a conductive mesh," Tomke Glier from the University of Hamburg.
The silver wires are typically several tens of nanometers thick and 10 to 20 micrometers long. The detailed X-ray analysis shows that the structure of the nanowires in the polymer is not changed, but that the conductivity of the mesh even improves thanks to the compression by the polymer, as the polymer contracts during the curing process.
The silver nanowires are applied to a substrate in suspension and dried. "For cost reasons, the aim is to achieve the highest possible conductivity with as few nanowires as possible. This also increases the transparency of the material," said DESY researcher Stephan Roth.
"In this way, layer by layer, a conductive path or surface can be produced," said Roth.
A flexible polymer is applied to the conductive tracks, which in turn can be covered with conductive tracks and contacts. Depending on the geometry and material used, various electronic components can be printed in this way.