Strong Red Emissions in Pr3+‐Doped (K0.5Na0.5)NbO3–CaTiO3 Diphase Ceramics

Abstract

The photoluminescence and temperature sensing properties based on down‐shifting emission of Pr3+‐doped (K0.5Na0.5)NbO3–yCaTiO3 (KNN: yCT) diphasic materials were systematically investigated. Under 447‐nm excitation, Pr3+‐doped KNN: yCT samples exhibited significantly enhanced red emission at 603 nm assigned to 1D2→3H4 transitions of Pr3+ ions. The red emission intensities reached the optimum value with y = 0.05 near the polymorphic phase transition region. The origin of the enhanced red emission is mainly ascribed to the doping‐induced lattice symmetry change. The energy level transitions from the typical f–f transitions to the valence‐to‐conduction transitions were observed as CaTiO3 concentration increases above a critical concentration of y = 0.05. Furthermore, the sample with y = 0.05 also possessed excellent temperature response properties in a wide temperature range 300–473 K and the maximum sensing sensitivity was 0.016 K−1. The Pr3+‐doped (K0.5Na0.5)NbO3–yCaTiO3 red emission materials with admirable intrinsic piezoelectric properties may have important technological promise in novel multifunctional devices.