A process was developed for 3D printing that can be used to produce transparent and mechanically flexible electronic circuits. The electronics consist of a mesh of silver nanowires that can be printed in suspension and embedded in various flexible and transparent plastics (polymers). This technology can enable new applications such as printable light-emitting diodes, solar cells, or tools with integrated circuits. The approach integrates electronics into existing structural units and improves components in terms of space and weight.
At the heart of the technology are silver nanowires that form a conductive mesh. The silver wires are typically several tens of nanometers (millionths of a millimeter) thick and 10 to 20 micrometers (thousandths of a millimeter) long. X-ray analysis shows that the structure of the nanowires in the polymer is not changed, but the conductivity of the mesh improves thanks to the compression by the polymer as it 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. In this way, layer-by-layer, a conductive path or surface can be produced. 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.
Researchers will test how the structure of the conductive paths made of nanowires changes under mechanical stress including how well the wire mesh holds together during bending and how stable the polymer remains.