Sustainable power generation from live freshwater photosynthetic filamentous macroalgae Pithophora

Photosynthesis is the natural eternal process of conversion of solar energy into Chemical energy by living chlorophyllous organisms. The direct conversion of sunlight into electrical current by using photosynthetic organisms has the potential to produce green energy. Conventional bio-photovoltaic cells have utilized unicellular photosynthetic microorganisms such as cyanobacteria and unicellular green algae. This study describes electricity generation through a quasi-solid-state device by utilizing live freshwater macroalgae. Here, we fabricated a simple bio-photovoltaic device with filamentous macroalgae Pithophora roettleri as photoactive materials. The filamentous alga Pithophora belonging to the family of green algae, is generally found growing at the bottom or forming dense mats on the surface of aquatic habitats. The algae were collected from a pond located in the neighbourhood and fabricated a device by sandwiching the algal biofilm between activated carbon-coated copper (Cu) and titanium oxide (TiO2) coated fluorine-doped tin oxide (FTO) coated glass slide. The fabricated optimized device has exhibited a considerable amount of photo-generated current and photo-generated voltage generation under the white light and UV light irradiation The optimized device (with 1 cm2 area) exhibits 10.19 μA short circuit photocurrent and 0.35 V open circuit photovoltage in white light (100 mW/cm2) irradiance and exhibits 1.25 mA photocurrent and 0.5 V photovoltage in UV light (365 nm LED with 20 mW/cm2 intensity). To understand applicability, 10 devices were connected in a series that delivered 5.53 V in outdoors under natural sunlight with 0.6 Sun intensity.