A team of researchers at the University of Minnesota have, for the first time, fully 3D printed an array of light receptors on a hemispherical surface. This discovery marks a significant step toward creating a “bionic eye” that could someday help blind people see or sighted people see better.
The research is published recently in Advanced Materials, a peer-reviewed scientific journal covering materials science. The author also holds the patent for 3D-printed semiconducting devices.
“Bionic eyes are usually thought of as science fiction, but now we are closer than ever using a multimaterial 3D printer,” said Michael McAlpine, a co-author of the study and University of Minnesota Benjamin Mayhugh Associate Professor of Mechanical Engineering.
Researchers started with a hemispherical glass dome to show how they could overcome the challenge of printing electronics on a curved surface. Using their custom-built 3D printer, they started with a base ink of silver particles.
The dispensed ink stayed in place and dried uniformly instead of running down the curved surface. The researchers then used semiconducting polymer materials to print photodiodes, which convert light into electricity. The entire process takes about an hour.
McAlpine said the most surprising part of the process was the 25 percent efficiency in converting the light into electricity they achieved with the fully 3D-printed semiconductors.
“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,” McAlpine said. “Plus, we can easily print a semiconducting device on a curved surface, and they can’t.”