|
For unique luminescence of the rare earth doped fluoride nanomaterials, these nanoparticles may find great applications in the fields of 3-D displays, bio-detection, solid-state lasers, anti-counterfeiting, infrared detection, and so on。The fluoride nanomaterials were synthesized by the sovlethermal method. The phase, stucture and morphology were analysised by X-ray diffraction, scansion electron microscopy (SEM), transmission electron microscopy (TEM). The XRD patterns were indexed to a pure YF3 orthorhombic phase and a pure LaF3 hexagonal phase. TEM and SEM images showed the morphology of YF3:Yb3+/Er3+, LaF3:Yb3+/Tm3+ and YF3:Yb3+/Tm3+, which were nanoclusters, nanosheets nanoparticles, microtubes, microrods.The ability of agent CTAB controlling the particle morphology and size were discussed.The upconversion spectrum was measured by Hitachi F-4600 spectrophotometer, under 978nm diode laser excitation. Stronger blue (4F5/2→4I15/2 and 2P3/2→4I11/2) and green (4S3/2, 2H11/2→4I15/2) upconversion emissions of Yb3+?Er3+ codoped YF3 rod-like nanoclusters were observed. The nanoparticles and nanosheets present strong ultraviolet and blue upconversion luminescence. There were six emission bands in the upconversion emission spectra of YF3:Yb3+/Tm3+, which peak at 291nm, 345nm, 361nm, 450nm, 475nm and 651nm. And they were corresponded to the 1I6→3H6, 1I6→3F4, 1D2→3H6 of Tm3+ cations.The relationship between upconversion relative intensity and pump power was also studied. Ground state absorption, excitation state absorption and energy transfer were used in discussing the upconversion mechanism of the nanocrystals and the pertinent upconversion mechanism models of the nanocrystals were proposed.
|