The Core-shell Structure Of Ag-SiO 2 Is The Same As That Of NaYF ₄ : Yb ^{3 +} / Er ^{3 + Performance Impact}

As the most important one in the up-conversion(UC) materials, NaYF4 was widely in many fields such as solar cells% 3D display and biological detection because of the unique and excellent photoelectricity property and the wonderful biocompatibility. It can improve the space of the application to make the NaYF4 (UC) material to be thin film. But the luminescent property is not very ideal by reason of the parity forbidden intra-4f electronic transition of the emitter of the rare earth. At present, it is a research hotpot through the UC being mixed or modified by the noble metal nanoparticles and the Ag is the most active one which can attract the people’s attention. In this paper, we introduced Ag nanoparticles into the UC film to enhance the NaYF4:Yb3+/Er3+luminescent emission intensity by using the localized surface plasmon resonance (LSPR) effect of Ag nanoparticles.Using hydrothermal method to prepare the NaYF4:Yb3+/Er3+ UC material and it is rare to put the UC powders to thin film with the whirl coating and washing and producing the core-shell structure Ag@SiO2 through hydrolyzing the TEOS with the Ag nanoparticles as the core and the SiO2 as the shell. We discuss the influence of different addition amounts of core-shell structure to the luminescence performance of NaYF4:Yb3+/Er3+UC materials. The structure, morphology and optical properties of NaYF4:Yb3+/Er3+and film with or without Ag@SiO2 have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy, respectively.Results show that 1) The XRD patterns indicated that the NaYF4:Yb3+/Er3+UC materials had perfect crystal structure and high purity six-party phase structure.2) The SEM images show that the UC were complete uniform size micro-rods crystal and the length is about 4um and the cross section diameter is lum. The film’s thickness is about 3um。3) The TEM pictures indicated that the side of the Ag nanoparticles is about 80nm, the thickness of the shell was dependent in the addition of the TEOS.4) PL spectrum revealed that the fluorescence luminous intensity of the UC material would be improved by adding the core-shell. The intensity of the NaYF4:Yb3+/Er3+ UC materials would be changed along with the addition and the thickness of the Ag@SiO2. The results showed the fluorescence luminous intensity of the UC materials would reach the best when the addition of the TEOS is 40uL in other word the thickness was 25nm and the mass ratio of the Ag@SiO2 and UC materials is about :4700.