Estudo e caracterização de novos corantes naturais para aplicação em células solares sensibilizadas

Abstract

This paper presents a study and characterization of dyes with flowers of plants collected in the Northeast of Brazil, such as Sida cordifolia (malva branca), the Catharanthus roseus (boa noite), Torenia fournieri (amor-perfeito-de-verão), Alamanda cathartic (alamanda da flor grande) and Cobaea scandens (sino de catedral). Was studied and observed the influence of flavonoids in the sensitization of natural dyes by means of a prototype solar cell with conductive film with a glass of SnO2: F produced by spray pyrolysis. The conductive glass was obtained precursor solution (HCl/H2O) containing of tin II chloride dihydrate (SnCl2.2H2O), ammonium fluoride (NH4F) and a slide glass heated to 600 ° C. The solution was sprayed on the heated substrate. About conductive glass was deposited a layer of titanium dioxide (TiO2). The layer was obtained by dissolving in commercial TiO2 powder acetic acid (CH3CO2H) and Triton X. The electrolyte was a solution of iodine / triiodide into the intracellular regeneration cycle, the counter electrode was a layer made of graphite. The plants were treated with a by washing with deionized water, drying with heat gun and Silica Gel to absorb moisture. Were macerated and immersed in an organic solvent. After a few days, were concentrated in a rotary evaporator at a speed 160 rpm at room temperature for 40 minutes. This dye was applied on the TiO2 layer and then the cell was tested under sunlight. The values obtained were: Torenia fournieri, short-circuit current = 0.44 mA and open circuit voltage V = 0.16; Catharanthus roseus, short-circuit current = 0.43 mA = 0 and open-circuit voltage, 14 V, Sida cordifolia, short-circuit current = 0.22 mA and open circuit voltage V = 0.19; Allamanda cathartic, short-circuit current = 0.19 mA and open circuit voltage V = 0.12; Cobaea scandens, short-circuit current = 0.32 mA and open circuit voltage = 0.17 V. These results may provide more data for better understanding and use of new natural dyes in solar cells.