The Eu 3+ -modified Bi 0.5 Na 0.5 TiO 3 (BNT) ceramics have been fabricated by the solid-state reaction method. The impact of Eu 3+ doping on the structure, photoluminescence, and electrical properties has been studied by XRD, SEM, PL spectra, and LCR meter. X-ray diffraction analysis reveals that the crystal structure of the samples is well matched with the trigonal perovskite, and the optimal temperature of presintering is 880°C. The Eu 3+ -doped BNT ceramics show excellent red fluorescence at 614 nm corresponding to the 5 D 0 → 7 F 2 transition of Eu 3+ under 466 nm excitation and relatively long fluorescence lifetime. The BNT-0.02Eu ceramic density is up to 5.68 g/cm 3 and the relative density is up to 94.6% with sintering temperature 1075°C. The piezoelectric constant (d 33 ) of samples has been significantly improved up to 110 pC/N by Eu 3+ doping. The BNT-0.03Eu ceramic presintered at 880°C and sintered at 1050°C has good dielectric properties and excellent luminescence properties. Eu 3+ -doped BNT ceramics make it potential applications for novel integrated electro-optical and multifunctional devices.
Qian Wang,Lin Zhang,Rui Li,Hui Yang,Chuanhui Wang,Zhao Xiong,Chunwu Liu
The excellent temperature stability and high saturation polarization of Bi0.5Na0.5TiO3(BNT) make it a promising candidate for energy storage capacitors. However, its disadvantages, such as low breakdown strength, high remnant polarization, and a complex sintering process, limit its further development. To address this, (1 −x) Bi0.5Na0.5TiO3−x Sr(Mg1/3Nb2/3)O3ceramics were fabricated, where ion doping was employed to modify the domain structure, reduce the grain size, and improve the energy storage performance. With the increase in dopant concentration, the evolution from long-range-ordered ferroelectric micro-domains into short-range-ordered randomly oriented polar nanoregions (PNRs) was revealed, as demonstrated by XRD and Raman spectroscopy. This resulted in a diffuse phase transition peak and a significant reduction in remnant polarization. However, the saturation polarization also decreased. Finally, the optimal energy storage performance was achieved at a medium dopant concentration (x= 0.10), accompanied by reduced grain size and a dense microstructure. This composition exhibited a discharged energy density of 1.64 J/cm3at a low electric field of 150 kV/cm, representing a notable improvement over pure BNT, which showed a highly lossy P-E loop and a discharged energy density of only 0.14 J/cm3at the same electric field.
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