Y2O3:Eu3+ nanotubes self-assembled into flower aggregates, uniform nanotubes and monodisperse nanospheres: shape controlled synthesis and luminescent properties

Abstract

Size-tunable Y₂O₃:Eu³⁺ flower aggregates constructed from nanotubes were obtained through rolling up Y(OH)CO₃ nanosheets under template-free hydrothermal conditions at 200 °C for 2 h, followed by an annealing process. Y(CH₃COO)₃ was used as a raw material for the preparation of Y(OH)CO₃ precursors through urea precipitation. The absorbed CH₃COO⁻ ions play an important role in the formation of nanosheet structures and PEG keeps the precursors monodisperse and uniform. Through decreasing the concentration of Y(CH₃COO)₃, smaller Y(OH)CO₃ flower assemblies of fewer nanotubes and homogeneously separated Y(OH)CO₃ nanotubes with the length of ∼150 nm and the diameter of ∼40 nm and monodisperse ∼30 nm Y(OH)CO₃ nanospheres, respectively, were also selectively prepared. After calcination at 600 °C for 2 h, the Y(OH)CO₃ were decomposed into Y₂O₃ and the tubular structures were maintained. Doped Eu³⁺ ions don't influence their morphologies. Under UV excitation, Y₂O₃:0.05Eu³⁺ flower-like and spherical samples show strong red emission, corresponding to the characteristic lines of Eu³⁺.