Microwave Hydrothermal Synthesis of Hexagonal NaYF_4 and Yb~(3+),Er~(3+)-doped NaYF_4 Microtubes

NaYF4 and Yb3+,Er3+-doped NaYF4(NaYF4∶Yb3+,Er3+) microtubes with a hexagonal structure were prepared by a simple microwave hydrothermal method at a relatively low temperature in a short period of time without using toxic trifluoroacetic acid.The starting reagents used in the preparation are Y(NO3)3(also using Yb(NO3)3 and Er(NO3)3 in the case of doping),NaF,citric acid,NaOH and ethyl acetate,and deionized water is used as the solvent.The as-prepared samples were characterized by X-ray powder diffraction(XRD) and scanning electron microscope(SEM).The effects of experimental parameters on the morphology and the crystal phase of the product were investigated.And the up-conversion photoluminescence properties of the NaYF4∶Yb3+,Er3+ microtubes were investigated.NaYF4 microtubes with single hexagonal phase are obtained by microwave heating method at a lower temperature in a short period.The formation mechanism of NaYF4∶Yb3+,Er3+ microtubes is proposed.The prepared NaYF4∶Yb3+,Er3+ microtubes have high luminescence intensity.