Synthesis of Eu-doped K0.5Na0.5NbO3 ceramics and their luminescent and dielectric properties

Abstract

K0.5Na0.5NbO3:xEu sol–gel powders and bulk samples were synthesized by means of a modified sol–gel method. Two types of samples were obtained via sintering at two temperatures. X-ray diffraction revealed the presence of the perovskite phase in materials obtained at both temperatures. Eu3+ emission and excitation studies were conducted to determine its luminescence response. For K0.5Na0.5NbO3:xEu sinters, the excitation spectra included narrow peaks in the VIS range due to the 5D0–7F1 and 5D0–7F2 relaxation processes. These transitions were indicative of the presence of Eu3+ at sites of low symmetry. Dielectric studies indicated that Eu2O3 affected the observed phase transitions. The influence of sintering temperature on structure and physicochemical properties was discussed.