Aplicação do corante da casca da berinjela em células solares fotossensibilizadas. / Application of dye from the peel of eggplant in photosensitizer in solar cells.

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

28/02/2011

RESUMO

Despite the efficiency of conventional solar cells reach about 20%, the cost of producing electricity using photovoltaic panels about 42 cents per kWh is still much higher than the cost of power generated by hydroelectric, 8 cents per kWh. Given the high cost of producing solar panels, woke up the interest in solar cells using dyes fotoexcitáveis known as Grätzel cells or DSC (Dye Sensitized Solar English Cells). For these cells the efficiency reaches about 10% when used artificial colorings of ruthenium complexes, but these compounds are difficult to be synthesized. Recent studies investigating the use of natural dyes containing anthocyanins show that they have the ability to convert solar energy into electrical sensitizing the semiconductor titanium dioxide reaching a conversion efficiency of 5- 6%. In view of this, woke up the interest in studying physical and chemical factors such as pH, solvent, temperature, concentration and copigmented ones that can influence the efficiency and stability of these dyes, in particular, this work from the bark of the purple eggplant (Solanum melongena). The dyes were extracted using ethaol solution with 0,1M HCl solution, ethanol HCl 1,5N (85:15), ethyl alcohol acidified with acetic acid and organic solvent ethanol-water (70:30) at different concentrations, and studies were made on the ability of the dye to absorb light, and cells from photosensitized dye with built using TiO2 and I-/I3 - as electrolyte. Analyses optical, ultraviolet, visible and infrared show that anthocyanins present in the peel of eggplant are best extracted with ethyl alcohol and acetic acid at a 1:2 w / v resulting in an intense peak in the visible region and an intense band in the range 3650-3200 cm-1 characteristic of the hydroxyl group. The cell with the organic solvent and added gallic acid, showed an increase in the photocurrent of 0.32 to 0.36 and 0.20 mA/cm2 to 0.23 mA/cm2, respectively, the same cells under illumination by two hours.

ASSUNTO(S)

célula solar sensibilizada por corante sensibilizadores naturais fisica dye-sensitized solar cell natural sensitizers

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