Interconversion of Perovskite and Fluorite Structures in Ce-Sc-O System

CeSeO3 was synthesized by a two-step synthesis route involving a combustion method followed by vacuum heating at 1100 degrees C in the presence of Zr sponge which acts as an oxygen getter. The compound was characterized by various techriques such as X-ray diffraction (XRD), high temperature XRD, thermogravimetry, diffuse reflectance (DR)-UV visible spectrophotometry, and Raman spectroscopy. Fluorite-type (F-type) solid solution with composition Ce(0.5)Sc(0.0)5O(1.75) was observed as an intermediate during the synthesis of CeScO3. Only by mere redox reaction was a reversible transformation between fluorite-type structure and perovskites structure observed. CeSCO3 was found as semiconducting oxide with band gap of 3.2 eV arising mainly between 0 p states in the valence band and Sc d and Ce d states in the conduction band with small contributions coming from Ce f and Sc p states. First-principles potential planE-wave-based calculations were performed for the band gap and its origin in CeSCO3. Photoluminescence measurement showed that CeSCO3 is a potential host material giving broad blue emission. This was further confirmed by demonstrating CeScO3 doped with 2 mol % Tb3(+) compound as an efficient green light emitter.