Influence of Eu valence in the optical activity of BaTiO3 decorated with CaF2 synthesized by microwave-assisted hydrothermal method
Inorganic hybrid materials are promising applications in absorbers and photon harvesting of solar irradiation, such as DSSC cell photoanodes. Moreover, the investigation of the interaction between the photoanode constituent materials is extremely important, since it is known that the properties of materials are strongly dependent on the nucleation and growth process. Therefore, the purpose of this work was the synthesis of a system consisting of a synergic combination of two inorganic hosts, BaTiO3 and CaF2, synthesized together through the microwave-assisted hydrothermal method, which allows obtaining single-phase materials in short synthesis times and low temperatures. The increase of optical activity was investigated after the insertion of Eu ions. From the structural results, it was possible to observe that the method used to obtain the system was efficient, even using temperatures as low as 140 oC for a reaction time of one minute in the plateau. The optical properties (emission and excitation) were evaluated in the visible and VUV region from 2.5 to 10.5 eV. The Xanes Eu LIII-edge differences associated to XEOL results indicate that the method of synthesis have incorporated the Eu3+ in the hosts and surface of the two compounds, BaTiO3 and CaF2. Therefore, the combination between the Eu3+ activators and F centers of the host increased the range for photon harvesting, making these systems a promising material for future applications in photoanodes for DSSC.