Blue sensitizers for solar cells: Natural dyes from Calafate and Jaboticaba

Blue-violet anthocyanins from Jaboticaba (Myrtus cauliflora Mart) and Calafate (Berberies buxifolia Lam) were employed as TiO2 dye-sensitizers. Solar cells sensitized by Jaboticaba extracts achieved up to Jsc=9.0 mA cm−2, Voc=0.59 V, Pmax=1.9 mW cm−2 and ff=0.54, while for Calafate sensitized cells the values determined were up to Jsc=6.2 mA cm−2, Voc=0.47 V, Pmax=1.1 mW cm−2 and ff=0.36. Other natural dyes were evaluated without significant photocurrent, demonstrating that only selected extracts are capable of converting sunlight in electricity. The results obtained with extracts of Jaboticaba and Calafate show a successful conversion of visible light into electricity by using natural dyes as wide band-gap semiconductor sensitizers in dye-sensitized solar cells. It also represents an environmentally friendly alternative for dye-sensitized solar cells with low cost production and an excellent system for educational purposes.