MIT Pushes Boundaries with Breakthrough for 3D Printed Electronics

Sometimes, innovation can be born out of coincidence. When MIT researchers were 3D printing magnetic coils out of polymer filament doped with copper nanoparticles, they noticed an unexpected quality in the material: it had a high resistance to electrical currents, and its levels would return to their original states when the flow of electrical current stopped. Why is this important? This is the quality that allows engineers to make transistors that can operate as swtiches. With this discovery, the MIT researchers had a new goal: to create the first fully 3D-printed, semiconductor-free, solid-state logic gates, and the first fully 3D-printed resettable fuses. The team succeeded, and this July, they published a paper on their devices.

Logic gates are devices that perform logical operations based on one or more binary inputs and produce one binary output—essentially, performing computation. Typically, they require semiconductors (often silicon or other materials), which have adaptable electrical properties. Silicon, for example, can have conductive and insulating regions depending on how its modified, making it optimal for producing transistors. Keeping in mind that transistors are the foundation of modern electronics, it’s notable that semiconductor devices are not widely available. They require specialized manufacturing facilities, and during the COVID-19 pandemic, the lack of semiconductor production facilities was one of the causes of the electronics shortage.

The 3D printed device and visualizations of its thermal conductivity (Photo credits: MIT)

So, the potential to create logic gates without the need for semiconductors opens the possibility for electronics to be created on a local level. The idea is still far from being a reality, but MIT researchers took a critical step towards that goal by 3D printing switches for logic gates. The production process used less energy and produced less waste than producing semiconductors, in part because the switches were printed using standard 3D printing hardware and inexpensive, biodegradable copper-doped polymer.