A Fruit Salad Recipe for Vision Restoration—Use of Natural Dyes for Photosensitive Organic Semiconductor Devices Toward Retinal Implants

Vision loss due to the degeneration of photoreceptor cells in the retina occurs in millions of people every year worldwide through diseases such as retinitis pigmentosa and age-related macular degeneration. The development of a photosensitive organic semiconductor device that can function in a way to replace lost or damaged photoreceptor cells may be a possible treatment for those suffering with these diseases. We demonstrate that natural dyes extracted from various berries and vegetables are excellent chromophore candidates for colour-specific organic devices with similar absorption spectra to those produced by human rod and cone cells. Using fabrication methods resembling those used in the development of dye-sensitised solar cells, bio-derived chromophores have been investigated and the production of active devices interfaced with electrolyte, phosphate buffered silane, have been demonstrated. Devices produce photo-current and photo-voltage spectra in the spectral regions corresponding to the activity of cones and rods. . Our results show the chromophores can respond to pulsed light in a similar way to photoreceptor cells and produce a rising photovoltage. In summary, we discuss if natural dyes can lead us to devices capable of stimulating neuronal circuitry in human eye.