Synthesis of monodisperse sub-3 nm RE₂O₃ and Gd₂O₃:RE³⁺ nanocrystals

Monodisperse, colloidally stable, sub-3 nm europium sesquioxide (Eu₂O₃), terbium sesquioxide (Tb₂O₃), and Eu³⁺-doped gadolinium sesquioxide (Gd₂O₃:Eu³⁺) nanocrystals have been synthesized via a hot solution-phase technique. The oleic acid concentration facilitated the production of the nanocrystals in a range of sizes from sub-2 nm up to 5.0 nm. The Eu₂O₃ and Gd₂O₃:Eu³⁺ nanocrystals exhibit new luminescence peaks at 620 nm, which correspond to modulation of the ⁷F₂ transition of the Eu³⁺ ion. The Tb₂O₃ nanocrystals express a new luminescence feature at 548 nm, which corresponds to modulation of the ⁷F₅ transition of the Tb³⁺ ion.