Fast Pyroprobe-Heating-Induced Structural Changes of Y₂O₃:Eu Precursors and Their Optical Signatures

Abstract

Luminescent europium-doped Y2O3 precursors are evaluated as potential ex situ thermal sensors for rapid heating events. The material is heated via pyroprobe for periods between 1 and 100 s. The morphological and optical properties of the material are measured as a function of heated temperature and dwell time. Upon heating, the material is believed to transform according to Y2(CO3)3 → Y2O(CO3)2 → Y2O2CO3 → Y2O3, with the transition to the crystalline Y2O3 phase occurring at about 666 °C. The optical spectra of the heat-treated samples reflect the presence of amorphous and crystalline components. The amorphous peak of the excitation spectra initially shifts to shorter wavelength and increases in width. With increasing temperature, a crystalline peak appears and grows in intensity while the amorphous peak disappears. By use of peak position and peak width, it is possible to monitor the temperature that the particles were exposed to.