Preparation And Upconversion Luminescnece Of Y₂O₃:Er³⁺, Yb³⁺ With Nanoporous Structure

The upconversion (UC) from infrared to visible of the materials doped with rare-earth (RE) ions has attracted much attention in the past few decades, due to their wide applications in such fields as upconversion lasers, optical-fiber-based telecommunications, three-dimensional displays, sensitive detection of biomolecules, and so on. The upconversion material Y2O3:Er3+,Yb3+is one of the most promising due to its high corrosion resistivity, thermal stability and low vibrational frequency and high efficiency of the upconversion.Nanoporous materials are of scientific and technological importance because of their special features, enabling them can be widely used in such fields as selective adsorption, delivery nanocapsules and biosensor, and so on.First, nanoporous structure Y2O3:Er3+was prepared by a simple hydrothermal method following by further heat treatment in this paper. And the samples have been characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM). From the FESEM, we cans see that the samples with different kinds of nanopouous structure were obtained by controlling the reaction time in the autoclave and the annealing temperature in the Muffle furnace. Under the laser excitation, the optical properties of the as obtained samples indicated that the regular and large nanoporous have positive impact on the enlargement of upconversion luminescence and the fluorescence decay time, but small and sparse nanoporous have negative impact. And the possible reasons were discussed.Second, the samples Y2O3:Er3+with different density of Er3+, and the samples Y2O3:Er3+,Yb3+with different density of Yb3+were made by the optimized reaction condition. The different density of Er3+,Yb3+have influence on the green and red upconversion intensity. The plots of logarithm intensity of the upconvesion emissions versus logarithm pumped power of diode laser prove the green emissions and the red emissions are both two-double-photon process. And through summarizing the conclusions of the experiment, the possible upconversion mechanisms in Y2O3:Er3+,Yb3+and Y2O3:Er3+were discussed.