CORANTES NATURAIS DE BATATA-DOCE ROXA E FRUTAS TROPICAIS APLICADOS EM CSSC

Abstract

The search for technologies that facilitate the reduction of dependence on fossil fuels as a primary energy source has been intensifying in recent years, through photovoltaic conversion has a prominent position for presenting low maintenance, long useful life, possibility of being installed in places remote areas and also because it is a form of clean energy. The main technology in this sector, cells built on silicon base have a high value in the cost of implantation. In order to seek more accessible ways, new projects, such as third-generation solar cells, are gaining prominence. These are emerging technologies, and among them are dye-sensitized solar cells (DSSC). They may have advantages in relation to the cost of production, versatility and diversity of materials that can be used in their manufacture. In these cells, semiconductor oxides such as TiO2 are used, combined with organic sensitizers (dyes). Synthetic dyes such as N719 have a high added value to their synthesis and distribution and, in order to reduce costs, another class of dyes can be used, being extracted from flowers and fruits. In plant diversity, many metabolites caused such as flavonoids, anthocyanins and carotenoids that in plants help against ultraviolet rays, absorbing sunlight. These have chromophore groups with photosensitivity characteristics, and this allows their use in DSSC. This dissertation aims to evaluate the efficiency of DSSC with natural dyes extracted from “in-natura” samples present in the epicarp (peel) of the National Black Plum (Prunus domestica L.), the skin of the Imported Black Plum (Prunus salicina L.), from the bark of the Purple Sweet Potato (Ipomoea Batatas L. Lam.), from the bark of Cambuí (Myrciaria Myciaria tenella) and also from the fruit of Myrtle (Eugenia gracílima Kiaersk). For use, a 70/30% methanol/water (v/v) solution is used, which is acidified at 3% with citric acid (m/v). For each sample, the screening of coloring substances was carried out in the proportion 1:1 (m/v), in order to obtain concentrated extracts, a second test was carried out for the same extract diluted in 50% of its concentration. For the extracts, the following were performed: quantification of anthocyanins by the differential pH method, UV-Vis Spectroscopy tests with 510nm absorption and Fourier Transform Spectroscopy (FT-IR). Electrochemical Impedance Spectroscopy (EIS) and Charge Extraction as a function of Time. The effects of electrochemical recombination were observed by Intensity Modulated Photocurrent Spectroscopy (IMPS) and Intensity Modulated Photovoltage Spectroscopy (IMVS). The photovoltaic devices were characterized by Photochronoamperometry, Current Density Curves vs Potential (j-V) the DSSC that stood out was for Plum A, showing Jsc= 0.482mA cm-2, Voc= 0.495V, FF= 0.374 and η= 0.0892% efficiency for the studied methodology.