There is a large economical and environmental interest on energy that comes from renewable resources. In this context, the solar energy arises like an interesting alternative because of its way of sustainable production, since no emission or pollutant generation occur, no production of noises or other byproducts during operation. Another advantage is related to the amount of solar radiation that reaches the Earth's surface, about 3x1024 J/year, marking the Sun a source of inexhaustible energy and able to withstand future energy demands.Dye sensitized solar cells are attractive because of their more accessible production process than the silicon solar cells, the last one is the current leader in the photovoltaic market. However, incorporating a redox couple I-/I3- and a liquid electrolyte introduce serious stability problems, including: solvent evaporation, leaks, corrosion and sealing difficulties in the device.An ideal alternative emerges with the development of solid and quasi-solid electrolytes. In this context, polymers provide a matrix in which a metal salt can dissolve, resulting in a conductive polymer. The use of complexes of transitions metals, such as cobalt and nickel, like redox couples are considered promising as alternative for I-/I3-. Recently, coordination complexes containing these centers have demonstrated that it is possible to obtain a DSSC with efficiencies greater than 12%.This project proposes the preparation and characterization of new solid and quasi-solid polymer electrolytes containing a particular polymers and as redox couples the pairs: Co (II) / (III) and Ni (III) / (IV) to be applied in DSSC, as an alternative to the current liquid electrolytes. The polymers to be used are: PVDF-HFP (copolymer of Polyvinylidene Fluoride Hexafluoropropylene), Polydimethylsiloxane (PDMS) and PVC (Polyvinyl Chloride). The prepared polymer electrolytes will be characterized by the techniques of Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Nuclear Magnetic Resonance (NMR), Electrochemical Impedance Spectroscopy and X-ray Diffraction. The solar cells will be characterized by the acquisition of the curve I vs. V, quantum efficiency as a function of wavelength (») curve and transient absorption spectroscopy. In this project we propose to study novel electrolytes that can reduce the problems associated with using a liquid electrolyte in DSSC. In a more detailed description, we will also evaluate the ionic conductivity, thermal properties and stability, in conjunction with an analysis of the solar cell's efficiency.
News published in Agência FAPESP Newsletter about the scholarship: