Células solares de TiO2 sensibilizadas por corantes amazônicos

Abstract

The use of solar energy through photovoltaic devices is one of the most promising alternatives for the use of renewable energy in the production of large-scale electricity. Among the most attractive photovoltaic devices for this purpose is the Dye-Sensitized Solar Cell (DSSC). One of the factors that can lower the cost of the device is the use of a natural sensitizer. This work has the interest of studying amazon natural dyes as sensitizer for solar cell of TiO2. Dyes were extracted from bark of Amazonian tree species Myrcia sylvatica and Byrsonima duckeana, and from leaves of Scutellaria purpurascens. These dyes were used as sensitized TiO2 films made by doctor blade. Visible ultraviolet (UV-vis) and infrared spectroscopy with Fourier transform (FTIR) were used to characterize the dye for DSSC. The presence of functional groups that can absorb light and inject electrons in the conduction band of TiO2 was confirmed, revealing the possible use in DSSC. The efficiency, under AM 1.5 conditions, of the best DSSC using the dyes M. sylvatica, B. duckeana, and S. purpurascens were 0.08%, 0.1% and 0.05%, respectively. When compared with the application of the N3 dye it is suggested that the natural dyes used present problems of recombination which may be related to the chemical nature of the compounds, since a high presence of carboxylic and hydroxyl groups prevents dye regeneration. But by the result obtained by the lower N3 of the literature, DSSC the base of these natural dyes can still be improved using, for example, a blocking layer to decrease the recombination of charges.