The purpose of this work is to associate the charge transfer effects with the high violet-blue emission observed in the Ba0.9Ca0.1Ti0.9Zr0.1O3 nanoparticles (BCZT-Np). The BCZT-Np were prepared by using the modified Pechini method. The structural and optical properties of BCZT-Np were determined by X-ray diffraction (XRD), Raman, diffuse reflectance Ultraviolet-Visible spectroscopy (UV-Vis), energy loss electron spectroscopy (EELS) and photoluminescence (PL) analysis. The Rietveld analysis for the XRD patterns and the normal phonon modes resolved by Raman confirm that powders synthetized at 700 oC for 1 h has a perovskite-type tetragonal structure with space group C4v1 (P4mm). It was found as an indirect electronic transition for BCZT-Np. The optical energy band gap values (Eg) measured by UV-Vis varies from 3.13 to 3.18 eV. These results are in agreement with the Eg values obtained by the energy loss function. An intense photoluminescence centered at 489 nm (blue emission) was observed in the BCZT-Np (Fig. 1a). This behavior could be associated to the presence of charge transfer effects. These results were confirmed by the interpretation of Ti (Fig. 1b) and Ca L2,3 edge using the multiplet calculation (based on a modified Hartree–Fock method) that includes the charge transfer effects. The PL results open the possibility to extend the potential application of this lead-free BCZT electro-ceramic for light-emitting devices.

Influence of charge transfer in the photoluminescence of lead-free Ba1-xCaxTi0.9Zr0.1O3 electro-ceramics

253rd National Meeting (2017)

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