The upconverted luminescence and chemical stability of morphologically controllable La2O3:Yb3+/Er3+ nanoparticles

Abstract

Morphology and size controls are critical for the research of luminescent nanomaterials. In this work, La 2 O 3 :18%Yb 3+ /2%Er 3+ nanoparticles were synthesized by a urea-assisted coprecipitation process, where the morphology and size of nanoparticles could be precisely controlled by adjusting the doping concentration, urea dosage and reaction time. With increasing Yb 3+ doping concentration and reaction time, morphological evolution processes from nanosheets to nanospheres to nanofibers were observed. The experimental results revealed that the nanospheres could only be synthesized when 18%Yb 3+ and 2%Er 3+ were doped into the La 2 O 3 host, where the size of the nanospheres could be precisely controlled by adjusting the urea dosage. The effects of the particle morphology and size on the upconversion luminescence of La 2 O 3 :18%Yb 3+ /2%Er 3+ nanoparticles were investigated. In addition, the chemical stability of La 2 O 3 :18%Yb 3+ /2%Er 3+ nanospheres in air was investigated by recording XRD and upconversion luminescence spectra after exposure to air for different periods. The experimental conclusions were useful for further probing the effects of the particle morphology and size on the upconversion emission of Er 3+ . The upconverted luminescence and chemical stability of morphologically controllable La 2 O 3 :Yb 3+ /Er 3+ nanoparticles. • La 2 O 3 :Yb 3+ /Er 3+ UC nanoparticles were synthesized via the co-precipitation method. • The morphology was controlled by adjusting doping concentration and reaction parameters. • The UC luminescence of La 2 O 3 :Yb 3+ /Er 3+ was associated with the particle morphology and size.