A Review of Bacterial-sensitizers for Photovoltaic Devices

Evolution has been optimizing proteins for light reception and energy conversion for more than 3.5 billion years. The use of genetic engineering and bio-dyes has provided an array of new materials that have enhanced properties. Dye-sensitized solar cells based on bio-photosensitizers (bio-sensitized DSSCs) are promising bio-photoelectronic devices for electrical energy preparation. In this paper, a comprehensive study was presented on the mechanisms involved in the utilization of bio-dyes for an improved bio-sensitized DSSCs performance. Protein complexes, and chlorophyll a and carotenoids are among many bio-photosensitizers demonstrating high incident photon-to-current efficiency (IPCE). Like other sensitizers, the band- gap is an important factor in final performance of the optical component. Theoretical-average HOMO-to-LUMO band-gaps of 2.46, 5.22, 4.13, 1.13, 3.15, and 2.22 eV were calculated for anthocyanin, carotenoid, chlorophyll, cyanine, xanthene, and coumarin, respectively. It is more probable that low dye band-gaps result in enhanced HOMO-electron excitation and e-h pair generation. The highest conversion efficiency for bio-DSSCs based on PPB+Spx is about 4%.