Poling-driven modulation of structural and luminescent properties in Eu3+-doped (1-x)(Bi1/2Na1/2)TiO3-xBaTiO3 relaxor

We investigated the structural, electric, and luminescent properties of Eu3+-doped (1-x)(Bi1/2Na1/2)TiO3-xBaTiO3 (BNT-xBT:Eu) relaxors for x = 0.0 – 0.08. The Rietveld refinement structural analysis revealed that the structural phase of BNT-xBT:Eu was the mixture of rhombohedral, monoclinic and tetragonal phases with significant x-dependence, which was in accord with the change in the emission spectra originating from Eu3+. Interestingly, we found that BNT-xBT:Eu for x > 0.4 experienced the structural phase transformation on application of electric field. The structural change by poling led to the reduction in the emission of Eu3+. Poling-driven emission quenching behaviors resulted from the increased local structure symmetry around Eu3+ in the poled samples. We also identified the photochromic behavior in our samples, in relation to the doping of Eu3+. These multi-functionality of BNT-xBT:Eu could pave a way to a new type of optoelectric material.