An optical device with an iridium oxide (IrOx) electrode neural interface, and a corresponding fabrication method are provided. The method provides a substrate and forms a first conductive electrode overlying the substrate. A photovoltaic device having a first electrical interface is connected to the first electrode. A second electrical interface of the photovoltaic device is connected to a second conductive electrode formed overlying the photovoltaic device. An array of neural interface single-crystal IrOx nanostructures are formed overlying the second electrode, where x.ltoreq.4. The IrOx nanostructures can be partially coated with an electrical insulator, such as SiO.sub.2, SiN, TiO.sub.2, or spin on glass (SOG), leaving the IrOx distal ends exposed. In one aspect, a buffer layer is formed overlying the second electrode surface, made from a material such as LiNbO3, LiTaO3, or SA, for the purpose of orienting the growth direction of the IrOx nanostructures.