Synthesis and characterization of perovskites with potential application in photovoltaic systems

Abstract

The search for renewable energy sources is widespread in society, since non-renewable sources have their scarce reserves and still disfavor the environment, so scientists have a great interest in solar energy since the sun is a clean source and practically inexhaustible. Solar cells are devices responsible for converting light energy into electrical energy. In this way, it is sought to use low-energy band gaps (Eg) in the active layer of solar cells, where the ideal value is approximately 1.4 eV. The perovskites are materials that show a great potential of application, since they can present an efficiency of conversion of solar energy in electrical greater than 20%. The ferroelectric oxides have band gaps between 2.7-4 eV, high values for application in solar cells, thus the discovery of complex perovskites, particularly KBiFe2O5 (KBFO), [KNBO3]1-x [BANi0,5Nb0,5O3-³] X (KBNNO), Bi2FeCrO6 (BFCO) with low Eg, has motivated studies for applications in solar cells. On the other hand, few reports on databases and phase equilibrium diagrams arouse scientific interest. Studying routes that make it possible to obtain powders of high homogeneity, with small particle size and with reduced temperatures is essential for the affordable commercialization of solar cells. Thus, the objective of this work is to obtain monophasic systems, with nanometric particles and small band gap and, for this, will use the chemical synthesis route by Combustion Solution (SCS), aiming at varying the stoichiometry of ions and collecting information that (composition / temperature) of possible solid solutions, set of compatible phases and pure phase. The results can then be organized in the form of a ternary phase diagram, using the binary diagrams that make up the respective phases, generating technical-scientific contributions to a better understanding of these materials for the generation of photovoltaic solar energy (sustainable energy). (AU)