The Preparation And Properties Of Rare-earth Doped Orthovanadates Materials

Rare earth doped materials have been of importance in recent years for their wideapplications including plasma display panel, telecommunications, energy conversion, andbiological imaging applications. Their wonderful luminescence properties, such as largeeffective Stokes shifts, sharp emission band and high resistance to photo bleaching andwidely emission bands from visible to near IR spectral regions make them attractivecandidates for use in multiplex assays. Among lanthanide ions, Europium ion (Eu3+) is ofgreat interests for its excellent PL property in visible range when doped into differenthosts, so Eu3+ions doped materials were widely studied. In this paper, the single crystals’preparation, structure and optical properties of YVO4:Eu3+, GdVO4:Eu3+andGdxY1-xVO4:Eu3+(x=0.2,0.4,0.6,0.8) under external high magnetic field were discussed.The main works include:(1) The crystals were grown by optical floating zone method. The fluorescencespectra of the crystals (including the excitation spectra and emission spectra) were studiedand found that the strong emission of Eu3+doped crystals no matter without magnetic fieldand under magnetic field up to50T. The effect of pulsed high magnetic field on integralintensity of electric-dipole emission spectrum of Eu3+in YVO4:Eu3+and GdVO4:Eu3+single crystals was studied and the results showed that magnetic field inducedluminescence suppression to YVO4:Eu3+and expansion to GdVO4:Eu3+. Strong effect ofthe magnetic field on the splitting and emission of5D0â†'7F2and5D0â†'7F4transition inEu3+was investigated. The integral luminescence intensities of Eu3+are proportional to themagnetic field at higher than15T. For GdVO4:Eu3+, the integral intensity increases withthe strengthening of magnetic field, and is completely opposite from YVO4:Eu3+. In thisstudy, the dependences of luminescence integral intensity to magnetic field should beattributed to the structure change induced by magnetic field which changes the symmetryof Eu3+ions in single crystals.(2) In order to further explore the Gd3+, Y3+ion interaction on the influence ofEu3+-dopted crystals, the series single crystals GdYVO4with different ratio of Gd3+to Y3+were prepared as substrate. It was found that the pulsed magnetic field also has the suppression and expansion effect to the GdxY1-xVO4:Eu3+PL spectra, but the impact is lessthan the GdVO4:Eu3+and YVO4:Eu3+. From the results, we can see that GdVO4:Eu3+andYVO4:Eu3+are much more sensitive to magnetic field, and are more suitable for used asmagnetic field detector.