Natural dyes can be used in dye sensitized solar cells (DSSCs) to generate low-cost devices, although with low light harvesting because of energy losses from the recombination process. This study investigates recombination reactions in DSSCs with natural dyes extracted from eggplants, plums, and hibiscus flowers. Titanium dioxide films were coated on a fluorine-doped tin oxide glass conductor substrate by the doctor blading method and impregnated in a dye solution for 24 h. Electrodeposited platinum was used as the cathode, and I3–/I– as the redox couple. The techniques employed were: intensity modulated photovoltage spectroscopy, intensity modulated photocurrent spectroscopy, electrochemical impedance spectroscopy, charge extraction, and cyclic voltammetry. The results show that cells containing plum dye exhibited the best photovoltaic parameters, with high values of gap, charge extraction, and potential, being less resistive to charge transfer with an electron lifetime of 0.51 s, collection time of 8.54 ms, and charge efficiency collection of 0.99.

In this work the characteristics of corrosion and inhibition of 1008 stainless steel in 0.5 mol.L-1 H2SO4 were investigated by physical and electrochemical methods. Organic compounds containing the heteroatom of N as benzotriazole (BTAH), tolytriazole (TTAH) and mixtures of BTAH + TTAH were used as corrosion inhibitors. The techniques used were: open circuit potential, anodic potentiodynamic polarization measurements, chronoamperometry, electrochemical impedance spectroscopy, weight loss and optical microscopy. The anodic polarization showed that the increase of both concentrations BTAH or TTAH diminishes the current density in all the potential anodic range studied; these results together with the weight loss measurements suggest that the inhibitors act by blocking the surface and that the interaction among them is only of destructive nature when inhibiting efficiency is approximated 100%, revealing that at low concentration both inhibitors act without affecting the mechanisms of the cathodic processes, but the anodic polarization curves in presence of the TTAH showed a strong inhibitive effect in all the potential range studied. However, both gravimetric and electrochemical results suggest a synergic effect for the inhibitive efficiency of the mixture 1.10-3 mol.L-1 BTAH + 1.10-3 mol.L-1 TTAH.