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Inorganic hybrid materials have promising applications in absorbers and for the photon harvesting of solar irradiation, such as in DSSC photoanodes. Moreover, investigation of the interactions between the photoanode constituent materials is extremely important, since it is known that the properties of the materials are strongly dependent on the nucleation and growth process. Therefore, the purpose of this work was to synthesize a system consisting of a synergic combination of two inorganic hosts, BaTiO 3 and CaF 2 , synthesized together through a microwave-assisted hydrothermal method, which allows single-phase materials to be obtained after short synthesis times and at low temperatures. The increase in 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 °C and a reaction time of one minute. The optical properties (emission and excitation) were evaluated in the visible and VUV region from 2.5 to 10.5 eV. The XANES Eu L iii edge differences associated with the XEOL results indicate that the synthesis method incorporated Eu 3+ in the hosts and the surface of the two compounds, BaTiO 3 and CaF 2 . Therefore, the combination between the Eu 3+ activators and the F centers of the host increased the range for photon harvesting, making these systems a promising material for future applications in photoanodes for DSSCs.

This paper reports a luminescence mechanism in Eu-doped BaAl2O4 excited with monochromatic X-rays (also known as X-ray excited optical luminescence - XEOL) from synchrotron radiation. The material was prepared via a proteic sol-gel methodology. The X-ray absorption near edge structures (XANES) at the Ba LIII- and Eu LIII-edges exhibit typical absorption spectra. XEOL spectra recorded in energy ranges, either around the Ba LIII- or Eu LIII-edges, showed important differences concerning the intensity of the Eu(2+) or Eu(3+) emission bands. Nevertheless, the total area under the XEOL spectra increases as the energy of the X-ray photons increases in both ranges (Ba LIII- and Eu LIII-edges).

This paper describes a new computational method for predicting the optical behaviour of doped inorganic materials. There is considerable interest in using inorganic materials in photonic devices, and in many cases, the optical properties of these materials depend on doping by ions such as those from the rare earth series. Among the inorganic materials of interest are the mixed metal fluorides (e.g. BaLiF(3), BaY(2)F(8), YLiF(4), LiCaAlF(6), LiSrAlF(6)), doped with trivalent rare earth ions. The paper describes the use of Mott-Littleton calculations to determine the optimum location for dopant ions, followed by crystal field calculations which make direct use of the output of the Mott-Littleton calculations to calculate the optical properties of the dopant ion taking into account its symmetry and the positions of the surrounding ions, including any vacancies or interstitial ions present by virtue of charge compensation. It is then possible to predict whether a given dopant ion at a particular site in a material will have favourable optical properties.