Structural, paramagnetic centres and luminescence investigations of the UV radiation-emitting BaZrO3:Gd3+ perovskite ceramic prepared via sol-gel route

초록

Perovskite-type ceramic materials have been widely studied due to their potential use in such applications as electrical, thermal, optical, and immobilizing host materials in nuclear waste. In this work, Gd3+-doped BaZrO3 perovskite samples were prepared by sol-gel method and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), electron paramagnetic resonance (EPR) spectroscopy, and photoluminescence (PL) analysis. Our XRD analysis confirmed the formation of the sol-gel products, and the SEM data implicated the prepared porous compound as the cause of the gases that evolved during the preparation. Upon excitation at 275 nm, the ceramic material displayed UVB emission at 315 nm (P-6(7/2) -> S-8(7/2)). The EPR technique was used to study the undoped and gadolinium-doped perovskite BaZrO3 ceramics. The lines in the undoped system were caused by two defect centers. Center I displayed an isotropic line with a g-factor of 1.973 and a linewidth of 48 Gauss, and the center was assigned to an F+ center. Center II exhibited an axially symmetric g-tensor with principal values g(parallel to) = 1.895 and g(perpendicular to) =1.978. This center was identified as the Zr3+ ion. The single dominant EPR line with an effective g-value of 1.976 that was observed in the Gd-doped system was attributed to the Gd3+ ion experiencing a weak cubic symmetry crystal field.

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