Active electronics are based on semiconductor components, the production of which in large quantities is only mastered by a few manufacturing centers worldwide. 3D printing a complete, active electronic device without semiconductors could enable the production of simple electronics in companies or laboratories.
The realization of this idea is still a long way off. However, a research group at the Massachusetts Institute of Technology (MIT) in the US has taken an important step in this direction by demonstrating fully 3D-printed resettable fuses, which are key components of active electronics that normally require semiconductors.
In another project, in which the researchers produced magnetic coils by 3D printing polymer filament doped with copper nanoparticles, they encountered an unexpected phenomenon: the introduction of a strong, electric current into the material caused the resistance to increase abruptly and return to its original level shortly after the current flow ceased. According to the researchers, this property makes it possible in principle to produce transistors that could act as switches and, in the next step, to form logic gates.
No deterioration even after 4,000 switching cycles
The 3D-printed, semiconductor-free components, which they produced using an inexpensive, biodegradable material, could in principle perform switching functions like semiconductor-based transistors. Although the technology is not suitable for competing with silicon semiconductors, it could be used for simple, basic control processes, according to the researchers.
The team has now used this phenomenon to print switches in just one process step, which could be used to produce semiconductor-free logic gates. The structures are made from thin, 3D-printed conductor tracks made from the copper-doped polymer. They contain intersecting conductive regions that allow the resistance to be regulated by controlling the voltage fed into the switch. Experiments showed that the components showed no signs of deterioration even after 4,000 switching cycles. The process consumes less energy and produces less waste.
In the future, researchers at MIT want to use this technology to print fully functional electronics. They aim to produce a fully functioning magnetic motor using only 3D extrusion printing.
