Optical and Morphological Characterization of Tb_0.01Zr_0.99O₂/(Precursor Eu_0.02Y_1.98O₃) Core/Shell Nanoparticles as Temperature Sensors in Fast Heating Events

Abstract

We characterize luminescent Tb0.01Zr0.99O2/(precursor Eu0.02Y1.98O3) core/shell nanoparticles as potential temperature sensors in fast heating events. The core of the nanoparticles consists of crystalline Tb0.01Zr0.99O2, while the shell is an amorphous Eu0.02Y1.98O3 precursor. When subjected to a brief thermal event, the crystalline zirconia core does not undergo any significant phase changes, whereas the yttria precursor shell undergoes an amorphous to crystalline phase change. Using this configuration, the emission intensity due to the Tb3+ ions in the ZrO2 core can be used as a reference. The emission intensity of the 5D0 → 7F2 transition of the Eu3+ ion in the initially amorphous yttria precursor increases with increasing temperature, providing an indicator for temperature. In addition, it is found that the emission intensity of the 5D0 → 7F1 transition of the Eu3+ ion does not depend on temperature and can also be used as a reference to determine temperature.