Upconversion luminescence of NaGdF4∶Yb3+,Er3+in rod-like structures
The rod-shaped structure of NaGdF4∶Yb3+,Er3+nanopowders was created by hydrothermal method using disodium ethylenediaminetetraacetate(EDTA-2Na)as chelating agent.By using X-ray diffraction(XRD),fluorescence spectrometry(PL),and scanning electron microscopy(SEM),the crystal structure,luminescence intensity,and surface morphology of NaGdF4∶Yb3+,Er3+were investigated and quantified.Herein,on the con-verted luminescence intensity on NaGdF4∶Yb3+,Er3+nanopowders,the impacts of experimental conditions of rare earth precursors,hydrothermal temperature and hydrothermal time were made an effective inquiry.Fluo-rine and sodium sources'effects on NaGdF4∶Yb3+,Er3+crystal shape and upconversion luminescence intensity were investigated.Meanwhile,the effects on the morphology and luminescence intensity of the samples were further investigated using the calcination procedure.The results of the experiment indicate that the most opti-mal luminescence intensity of NaGdF4∶Yb3+,Er3+is obtained from a rod structure that using NH4F and NaOH as fluorine and sodium sources respectively and undergone calcination at 200 ℃ for 1 hour.As a result,the green luminescence purity,measured through the Commission Internationale de Ieclairage(CIE),was signifi-cantly improved from 84％to 94.88％.
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