USO DE CORANTES NATURAIS EM CÉLULAS SOLARES DE TiO2

Abstract

The burning of fossil fuels, releases into the atmosphere high amounts of polluting gases, which brings harm to the fauna and flora. In this perspective, the sources of renewable energies come to have high prominence, since they are able to reduce the emission of pollutants and can supply the world energy demand. Among the innovative and recent methodologies being studied, there are dye senstized solar cells (DSSC). These systems use a semiconductor oxide, such as TiO2, on its impregnated surface, a dye, which is responsible for absorbing energy and ejecting the electrons to the valence band (BV), providing an electric current. In order to reduce costs, there is a need to research new dyes, capable of being used in these devices, such as those extracted from flowers and fruits for the use of natural products. This work aims to evaluate the use of natural dyes in third generation TiO2 devices. The devices were characterized by: Scanning Electron Microscopy (SEM), UV VIS Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), Open Circuit Potential as a Function of Time (Voc), Photocronoamperometry, Cyclic Voltammetry, and Curves of Current Density vs Potential (j-E). For the recombination analyzes, the following techniques were used: Cyclic Voltammetry, Photocurrent Spectroscopy with Modulated Intensity (IMPS) and Photovoltage Spectroscopy with Intensity Modulation (IMVS). All solar cells had natural dye adsorption, with good loading / unloading injection. The electrochemical techniques showed that the best cell, with lower resistance to transfer of charge and with better photovoltaic parameters was with the dye extracted from the plum, which presented a jsc = 0.635 mA cm-2

, Voc = 522 mV, FF = 0.604, τr = 0.51, τc = 2.35 ms and a gap of 1.79eV.