Duke engineers 3D print eco-friendly transistors with water

Researchers at Duke University have created environmentally friendly, fully recyclable printed electronic components that use water instead of industrial chemicals in the manufacturing process.

Using carbon-based inks, including semiconducting carbon nanotubes, conductive graphene, and insulating nanocellulose, engineers were able to stack multiple layers of components.

However, the team struggled to produce a high current of electrons using a water-based ink, which made it difficult to create complex electronic devices. The surfactant used to prevent clumping also made it difficult for additional layers to adhere to the first.

The researchers improved their method by switching to a cyclical process in which the device is rinsed with water, dried, and reprinted. They reduced the amount of surfactant used in the ink to create fully functional, fully recyclable, and fully water-based transistors. They chose to print the transistors first, due to the relative complexity of the tiny devices, compared to simpler components like resistors. In doing so, they have set a very high bar to show by example what this process is capable of.

The team has already shown that almost 100% of the carbon nanotubes and graphene used in their printing process with those inks can be recovered and reused. The nanocellulose found in the other carbon-based ink is made from wood, so it can simply be recycled or biodegraded.

Although the process uses a lot of water, it’s not as much as is required to deal with the toxic chemicals used in traditional manufacturing methods.

Thanks to this one-of-a-kind demonstration, research suggests a more environmentally friendly future for the electronics industry is possible.

The research has been published in a paper titled “All-Carbon Thin-Film Transistors Using Water-Only Printing,” which you can find in the journal Nano Letters, at this link.

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