Synthesis and characterization of rod-like Y2O3 and Y2O3:Eu3

Y₂O₃ rods 100 to 200 nm in diameter and 10 to 20 μm in length are accessible via polyol-mediated synthesis of a precursor material with similar shape. By heating of Y(CH₃COO)₃ · xH₂O and a defined amount of water at 190°C in diethylene glycol, the rod-like precursor material is formed. Infrared spectroscopy (IR), differential thermal analysis (DTA) and thermal gravimetry (TG) evidence that this precursor material still contains acetate. However, the precursor material can be transformed to Y₂O₃ by sintering at 600°C without destruction of the rod-like shape. According to X-ray powder diffraction analysis, the rods are well crystallized. They can be assumed to be with [100] orientation. By doping with Eu³⁺ (5 mol%), red emitting phosphor rods can be realized. With optical spectroscopy the typical line emission of Eu³⁺ is observed. Diffuse reflectance of Y₂O₃:Eu³⁺ rods is determined to be higher than 95% in the visible. While exciting at 254 nm (Hg-discharge), a quantum efficiency of 38.5% is proven for the prepared Y₂O₃:Eu³⁺ rods.