Using a custom-built 3D printer, they started with a base ink of silver particles. The dispensed ink remained 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 is said to take about an hour.
“Bionic eyes are usually thought of as science fiction, but now we are closer than ever using a multimaterial 3D printer,” said Michael McAlpine, Associate Professor of Mechanical Engineering.
He added that the most surprising part of the process was the 25% 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.”
According to McAlpine, the next steps are to create a prototype with additional light receptors that are more efficient. They will investigate also a way to print on a soft hemispherical material that can be implanted into a real eye.