A team of researchers has edged one step closer to developing a "bionic eye" that could one day help cure blindness.
The breakthrough by researchers at the University of Minnesota comes in the form of a prototype that was created by fully 3D printing an array of light receptors on a hemispherical surface.
"Bionic eyes are usually thought of as science fiction, but now we are closer than ever using a multi-material 3D printer," said Michael McAlpine, co-author of the research study and University of Minnesota Benjamin Mayhugh Associate Professor of Mechanical Engineering.
The prototype was started with a hemispherical glass dome, which researchers used 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, a process that takes about an hour.
McAlpine said 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.
"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 micro-fabrication facilities," McAlpine said.
He continued: "Plus, we can easily print a semiconducting device on a curved surface, and they can't."
McAlpine says 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.
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