Chlorophyll-c from marine algae and its characterization as natural dye for dye-sensitized solar cells.

Marine algae (seaweeds) have a broad range of applications in several productive sectors, from human consumption to pharmacology, cosmetics, agriculture and waste water treatments. Algal biomass are also employed in the field of renewable energies for the production of biogas. Marine algae are indeed a reserve of natural dyes (Chls a, b and c), being therefore potentially suitable in PV technology for their low cost and easy attainability, without potential environmental load in terms of land subtraction. Chlorophyll-c is a photosynthetic pigment, a porfirine molecule, presents only in brown algae. Undaria pinnatifida (known as Wakame) is largely present in Venice Lagoon and for it a disposal strategy is recommended. In this study, a low cost and eco-friendly extraction protocol was developed to obtain chlorophyll-c from brown alga Undaria pinnatifida, for utilization in dye-sensitized solar cells (DSSCs), along with the characterization of optical absorption and spectroscopy of the dye. Photovoltaic performances of the chlorophyll-based devices were also tested by measuring current-voltage curves as well as the incident photon to current efficiency. Three different solvents were tested, whose polarity was modified with different dilution with water. Better chlorophyll-c was extracted using 60% of acetone, whereas Ritchie algorithms were used to determine chlorophyll concentrations. The UV absorbance spectrum of chlorophyll extract exhibits the characteristic absorption peaks at 630 nm, confirming the presence of chl-c. The DSSC has delivered a short-circuit photocurrent density (Jsc) of 1.739 mA/cm2, open circuit photo-voltage (Voc) of 0.407 V, fill factor (FF) of 0.67, an efficiency (η) of 0.49% and a maximum incident photon-to-current conversion efficiency (IPCEmax) of 16% atthe Soret peak. The data presented here, improving η and IPCEmax , exceed the prior art of our previous study.[1] Obtained data suggest that protocols developed are useful to get an optimum amount of chlorophyll-c and that the DSSC performance indicates the possible use of marine algae in sustainable energy technologies.[1] G. Calogero, I. Citro, G. Di Marco, S. Armeli Minicante, M. Morabito and G. Genovese, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 117 (2014) 702.