Preparationand Analyses Of Structure&Up-converted Luminescent Properties Of Yttrium Stabilized Zirconiapowders

In various oxide up-converted hosts, zirconia has caught a lot ofhuman attentions due to its relative low phonon energy, however, itexhibits physical and chemical instabilities when it is calcined at differenttemperatures, that restricts its applications. In this thesis, single-dopedand double-doped samples8YSZ:RE3+/Yb3+(RE is Er,Ho or Tm) thatchoosing yttrium stabilized zirconia Zr0.92Y0.08O1.96(hereafter noted as8YSZ) as host were prepared via chemical co-precipitation, and theypresent up-converted luminescence, and then the dependent relationshipof up-conversion luminescence on synthetic temperature and single ordouble doping concentrations of rare earth ions was illustrated. Finally,the probable up-conversion mechanism was also discussed. The resultsare listed below:(1) samples calcined at600~1300℃are polycrystal powders andthe phase structures are face cubic which means that8mol%yttrium ionscan stabilize high temperature cubic zirconia;(2) high temperatures do well to crystal growth, defects reduction andthe up-conversion intensity improvement, samples calcined at1200℃for3hours own pure stabilized cubic phase and good crystallinity, so itsup-conversion intensity is strongest under980nm infrared excitationï¼›(3) under980nm infrared laser irradiation,8YSZ:Er3+/Yb3+sample oflow doping concentration emits green light corresponding toEr3+:2H11/2/4S3/2â†'4I15/2transitions, while the high counterpart emits redlight corresponding to Er3+:4F9/2â†'4I15/2transition,8YSZ:Ho-Yb samplepresents three characteristic bands of Ho3+ions, viz. green (Ho3+:5S2/5F3â†'5I8), red(Ho3+:5F5â†'5I8) and infrared (Ho3+:5S2/5F3â†'5I7), while theup-conversion intensity of8YSZ:Ho sample is quite weak and itsemission peaks are complex.8YSZ:Tm-Yb sample presents weakcharacteristic blue emissions of Tm3+ions corresponding to Tm3+:4G1â†'3H6transition, the fluorescence of8YSZ:Tm3+sample is negligible, Yb3+ions can improve up-conversion efficiency, moreover, there aremany Stark splits in some emission peaks;(4) the main two mechanisms in single-doped up-conversionprocesses are excited state absorption (ESA) and cross relaxation (CR)while in double-doped samples the mechanisms are energy transfer (ET)and energy back transfer (EBT), causing the up-conversion luminescencedependence on rare earth doping concentration;(5) in these experiments, samples8YSZ:0.001Er-0.11Yb and8YSZ:0.001Ho-0.07Yb obtained the strongest green emissions, sample8YSZ:0.09Er-0.07Yb obtained the strongest red emissions, and sample8YSZ:0.0005Tm-0.05Ybobtained the strongest blue emissions.