Dye-sensitized solar cells using natural dyes have lower cost when compared to ruthenium-based dyes. This paper aims to evaluate, electrochemically, solar cells composed of TiO2 with dye extracted from the Hibiscus(var. Sabdariffa) and propose an adsorption model capable of predicting the adsorption mechanism of the dye on the semiconductor surface. The characterization techniques used were: Fourier Transform Infrared Spectroscopy, UV-VIS Spectroscopy, Measurement of the Open Circuit Potential, Photocronoamperometry, and Current Density Curves vs. Potential. The infrared spectroscopy confirmed there was adsorption of dye on the TiO2 surface. The adsorption isotherm with the better value of linear coefficient (R= 0.9874) was the Langmuir isotherm. The electrochemical techniques showed that the best cell prepared from a solution with a concentration of 5.27 mg L-1 of the natural dye, had an Eca= 516 mV, j = 0.15 mA cm-2 and an energy efficiency (η) of 0.15%.
Keywords:
photovoltaic cells; natural dyes; anthocyanin
