New York, Aug 29 : Researchers have, for the first time, fully 3D printed an image sensing array on a hemisphere, which is a first-of-its-kind prototype for a "bionic eye", that could someday help blind people see or sighted people see better.
"Bionic eyes are usually thought of as science fiction, but now we are closer than ever using a multimaterial 3D printer," said Michael McAlpine, from the University of Minnesota.
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.
In the paper, published in the journal Advanced Materials,the most surprising part of the process was the 25 per cent efficiency in converting the light into electricity they achieved with the fully 3D-printed semiconductors, McAlpine said.
"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," he said.
The next steps are to create a prototype with more light receptors that are even more efficient.
They'd also like to find a way to print on a soft hemispherical material that can be implanted into a real eye, McAlpine noted.