Heptamethine cyanine dyes working as light harvesting antennas in biohybrid photosynthetic assemblies

Nature solved the problem of converting solar light into chemical energy in a very elegant way through the photosynthesis. The natural photosynthetic process takes place thanks to a very precise protein scaffolding architecture and pigments arrangement that lead to convert 98% of the absorbed photons into a stable charge separated state with a lifetime in the second timescale. An intelligent way towards the design of artificial devices for solar conversion is to try to learn the lesson from Nature by mimicking the organization of the natural photosynthetic process. The interest of the scientific and industrial world towards a system capable of storing sunlight and convert it into a suitable form of energy has been increasing markedly in recent years. The idea is to focus on the natural candidates capable of performing these tasks, the photosynthetic reaction center proteins (RC), whose photochemical properties, selected by nature in the evolution course, however, are complicated to reproduce in artificial device. Hybrids have as central protein the photosynthetic reaction center from the purple no sulphur bacterium Rhodobacter sphaeroides strain R26, that converts solar light into a electron-hole couple state having an adequate lifetime to allow the ancillary chemistry to happen.