Implants with Gallium Solar Cells: A Light of Hope for the Blind?

Diseases such as age-related macular degeneration are accompanied by the deterioration of photoreceptors, the sensory cells responsible for color perception. Medical neuroprosthetics offers a therapeutic approach with devices that interact with the nervous system to restore lost functions. A well-known example of such approaches is cochlear implants for the deaf, which convert sound into electrical signals. Photovoltaic implants operate on the same principle, converting light into color perceptions. A crucial advantage of this technology is that no wires need to be implanted into the eye, which is a very complex procedure.

Currently, the research project is in the “Proof of Concept” phase, demonstrating fundamental feasibility. So far, tests have been exceptionally successful. The researchers modeled the mini solar cells for the eye after thin-film solar cells made from semiconductor materials such as gallium arsenide and gallium indium phosphide. These flexible solar cells are much lighter than thick-film silicon modules. To generate sufficient voltage for neuron stimulation, multiple layers of the material are required. Gallium arsenide, in particular, is therefore very promising as a material for implants, as it can be layered much more easily than silicon. Furthermore, these solar cells achieved very high efficiencies of almost 69% in tests conducted by the Fraunhofer Institute.

Not only gallium, but also indium is used in the development of optical implants (as we previously reported). Because both technology metals are becoming increasingly relevant in the fields of high technology as well as medical materials research, investors should definitely keep an eye on them.