Eu³⁺:Y₂O₃ microspheres and microcubes: A supercritical synthesis and characterization

A new approach that uses mixed supercritical solvents of water/1-propanol and water/methanol (400 °C, 40 MPa) to prepare morphology-controlled precursor materials in a very short reaction time, such as 10 min, followed by calcinations has been developed to form Eu³⁺:Y₂O ₃ microspheres of 2-3 μm in diameter or microcubes of 2-3 μm in side length, respectively. Eu³⁺:Y₂O₃ microspheres and microcubes exhibited strong red emission at 610 nm corresponding to ⁵D₀→⁷F₂ transition. The highest photoluminescence emission was obtained for the microspheres after calcination at 1000 °C for 1 h in air.