For the new development, scientists from the University of Minnesota began with a hemispherical glass dome. This was to figure out how the challenge of printing electronics on a curved surface could be overcome. From this they constructed a custom-built 3D printer. The printer used a base ink of silver particles. After several iterations it was found that the dispensed ink could remain place and be dried uniformly. This was in contrast to the ink running down the curved surface, as would happen in the unmodified state.
For the final stage, the scientists used semiconducting polymer materials in order to print photodiodes. These convert light into electricity. The current is generated when photons are absorbed in the photodiode. Once the technique had been perfected, the entire process was reduced down to one hour.
The technique is detailed in the following video:
The prototype has 25 percent efficiency in converting the light into electricity with the 3D-printed semiconductors. The success led lead researcher Michael McAlpine to state: “Bionic eyes are usually thought of as science fiction, but now we are closer than ever using a multimaterial 3D printer.”
The aim is to now bring 3D printing, electronics, and biology onto a single platform. This will provide the basis for a bionic eye, and other future bionic components like a bionic ear. With the eye concept, the prototype with be developed further so that it has even more light receptors with greater efficiency. A second aim is to print the structure onto a soft hemispherical material so that it can be safely implanted into a real eye.
The research has been published in the journal Advanced Materials. The research paper is titled “3D Printed Polymer Photodetectors.”
