Synthesis and luminescent properties of sub-5-nm lanthanide oxides nanoparticles

We introduce a new method for the synthesis of luminescent nano-sized particles. Ultrafine, equiaxed and monodisperse rare-earth oxide particles with an average grain diameter in the range 2–5 nm have been prepared by applying direct precipitation from high-boiling polyalcohol solutions. Colloidally stable suspension of luminescent nanoparticles is formed. The lanthanide doped nanoparticles are easily, quantitatively and reproducibly prepared. The materials have been characterized by using high-resolution TEM, absorption spectroscopy and luminescence spectroscopy. A very significant modification of the luminescent properties is observed. Lanthanide sesquioxides Ln2O3 and doped Ln3+ yttrium or gadolinium oxides are presented (Ln=Eu, Tb, Nd).