Preparation And Luminescence Properties Of Rare Earth Doping Of AlF3-YbF3Up-Conversion Phosphor

Up-conversion light-emitting materials have shown tremendous potential applications in the fields of solid-state lasers, three-dimensional stereoscopic display, backlight and biometric technology. Therefore, the research on up-conversion light-emitting materials is of not only important scientific significance but also great application value. The researchers have been developed many kinds of up-conversion light-emitting materials through decades of the efforts. However, only NaYF4and in Y2O2S can be really practical used. Based on this, to explore novel and high efficient up-conversion light-emitting materials is still one of the key issues in up-conversion luminescence research fields. In this paper, AlF3-YbF3:Er3+phosphor and AlF3-YbF3:Tm3+phosphor were synthesized and luminescence process of AlF3-YbF3: Er3+phosphor and AlF3-YbF3:Tm3+phosphor were studied. In addition, white up-conversion phosphor were synthesized though Er3+and Tm3+ions co-doped into AlF3-YbF3powder, multi-step energy transfer processes of from Yb3+ions to Er3+ions、from Yb3+ions to Tm3+ions and from Tm3+ions to Er3+ions were preliminary studied.1. AlF3-YbF3:Er3+phosphor were prepared by high temperature solid state method. The crystal structures of the phosphors were characterized by means of X-ray diffraction (XRD), it can be seen from X-ray diffraction:white up-conversion phosphor AlF3-YbF3:Er3+contains rhombohedra AIF3phase and orthorhombic YbF3phase; It can be seen that from up-conversion fluorescence spectra: the spectrum of AlF3-YbF3:Er3+phosphor include blue peak (410nm)、green peak(550run) and red peak(660nm). violet peak(410nm), green peak (550nm) and red peaks(660nm) are due to2H9/2�'4I15/2、4S3/2�'4Iis/2and4F9/2�'4Iis/2energy level transition of the Er3+ions, and when the Er3+concentration is fixed to be0.7mol%, the maximum red emission intensity can be obtained in the sample. The research results show the fitted slopes were3.64,2.72and2.24for blue, green and red transition emission, respective, indicating that blue emission owed to a four-photon excitation process, while, green transition emission is three-photon excitation process and red transition emission is two-photon excitation process.2. AlF3-YbF3: Tm3+phosphor were prepared by high temperature solid state method. The crystal structures of the phosphors were characterized by means of X-ray diffraction (XRD), it can be seen from X-ray diffraction:white up-conversion phosphor AlF3-YbF3: Tm3+contains rhombohedra A1F3phase and orthorhombic YbF3phase; It can be seen that from up-conversion fluorescence spectra: the spectrum of AlF3-YbF3:Tm3+phosphor include UV peak (360nm)、blue peak (410nm)、red peak(550nm) and near-infrared peak(800nm); UV peak (360nm)、violet peak(410nm), red peak (700nm) and near-infrared peak (800nm) are due to1D2�'3H6,1G4�'3H6,1G4�'3F4and3H4�'3H6energy level transition of the Tm3+ions, and when the Tm3+concentration is fixed to be0.3mol%, the maximum UV emission intensity can be obtained in the sample. The research results show the fitted slope for UV transition emission is2.96, which indicated that red emission is due to a three-photon excitation process, while, blue and red transition emission is three-photon excitation process and near-infrared transition emission is two-photon excitation process.3. Er3+and Tm3+co-doped AlF3-YbF3phosphor was prepared by high temperature solid state method. The crystal structures of the phosphors were characterized by means of X-ray diffraction (XRD), it can be seen from X-ray diffraction:white up-conversion phosphor AlF3-YbF3:Er3+/Tm3+contains rhombohedra AIF3phase and orthorhombic YbF3phase; Conversion energy transfer mechanism of phosphors and the concentration effect of Tm3+on color coordinates of phosphors were studied through the emission spectra of the phosphor. The results showed that:in the980nm laser excitation, violet peak(410nm), green peak (550nm) and red peak (660nm) are due to2H9/2�'4I15/2、4S3/2�'4I15/2and4F9/2�'4I15/2energy level transition of the Er3+ ions, while UV peak(360nm)、blue peak(450nm) and red peak(700nm) are corresponding to1D2�'3H6、1G4�'3H6and1G4�'3F4energy levels transition of Tm3+ions. Finally, blue peak, green peaks and red peaks are mixed into the white light (color coordinates:x=0.32, y=0.36).