A Biogenic Photovoltaic Material.

A proof-of-concept for the fabrication of genetically customizable biogenic materials for photovoltaic applications is presented. E. coli is first genetically engineered to heterologously express the carotenoid biosynthetic pathway from plants. This modification yields a strain that overproduces the photoactive pigment lycopene. The pigment-producing cells are then coated with TiO2 nanoparticles via a tryptophan-mediated supramolecular interface, and subsequent incorporation of the resulting biogenic material (cells@TiO2 ) as an anode in an I- /I3- -based dye-sensitized solar cell yields an excellent photovoltaic (PV) response. This work lays strong foundations for the development of bio-PV materials and next-generation organic optoelectronics that are green, inexpensive, and easy to manufacture.