Photo- and radiation-induced preparation of Y₂O₃ and Y₂O₃:Ce(Eu) nanocrystals

A convenient method for preparation of pure and doped yttrium oxide was developed, which is based on irradiation of solutions containing yttrium nitrate and ammonium formate with UV light or accelerated electrons. Solid phase formed under irradiation was consequently calcined at 500 °C or higher temperatures to obtain nanocrystalline yttrium oxide. Addition of small amount of cerium(III) or europium(III) nitrates to irradiated solutions resulted in doping of yttrium oxide with Ce(III) or Eu(III) ions. Under both types of irradiation, the method yields material with high specific surface area, consisting of spherical nanoparticles 25–100 nm in diameter depending on preparative conditions and post-radiation treatment and with narrow size distribution. In the doped oxides (Y₂O₃:Ce or Y₂O₃:Eu), radioluminescence spectra typical for Ce³⁺ or Eu³⁺ doped oxide structures were observed.