Abstract

A new method to produce scandium oxide nanoparticles with dimensions <80 nm is reported. This method could be of great interest for homogeneous incorporation of scandium oxide in specific materials, and in the production of thin Sc₂O₃ films. Colloidal particles of oxo–hydroxo scandium were synthesised by the sol–gel method. The particle morphology was characterised by TEM analysis. The particles so formed were lozenge shaped platelets (ca. 66 × 37 × 4.5 nm) and were highly stable in suspension in alcoholic solution. The xerogel material was produced by slowly evaporating the solvent from the sol. Its thermal stability, structure and composition were deduced from XRD, TGA–DSC, N₂-BET isotherms, ¹³C{¹H} NMR CP MAS and FTIR investigations. The particle morphology was retained upon calcination at 773 K, and the bulk xerogel exhibited a mesoporous structure with a surface area of 180 m² g⁻¹. Sc₂O₃ porous xerogel optical coatings were produced on fused silica substrates by dip coating. As shown by UV transmission experiments, these films exhibited a high transparency in the wavelength range 200–1000 nm, and refractive indices up to 1.84 at 350 nm when calcined at 773 K.