University of Minnesota researchers have, for the first time, fully 3D-printed an array of light receptors on a hemispherical surface, or in other words, a significant step toward creating a “bionic eye” that could someday help the vision impaired. The researchers started with a hemispherical glass dome to see if they could overcome the challenge of printing electronics on a curved surface, and did so successfully with a custom-built 3D printer. The dispensed ink stayed in place on a base ink of silver particles, and dried uniformly instead of running down the curved surface. Then the team used a semiconducting polymer materials to print photodiodes, which convert light into electricity, with the entire process taking about an hour. Read more for another video and additional information.
Michael McAlpine, a co-author of the study and University of Minnesota Benjamin Mayhugh Associate Professor of Mechanical Engineering, stated that the most surprising part of the process was the 25% efficiency in converting the light into electricity, in which they achieved with the fully 3D-printed semiconductors. He says the next steps are to create a prototype with additional light receptors that are even more efficient, while also finding a way to print on a soft hemispherical material ready to be implanted into a real eye.
“We have a long way to go to routinely print active electronics reliably, but our 3D-printed semiconductors are now starting to show that they could potentially rival the efficiency of semiconducting devices fabricated in microfabrication facilities. Plus, we can easily print a semiconducting device on a curved surface, and they can’t,” said McAlpine.