Preparation And Luminescence Propcrtics Of Rare Earth Doped Zirconia Nanocrystalline

In recent years, the development of newly green energy has become a hot spot ofresearch. White LED and solar cells possess many advantages of energy saving,environmental protection and security as new energy source. Zirconia has a good chemicalstability and thermal stability as matrix material. The paper has adopted sol-gel process tosynthesize different crystal phase structure of rare earth doped Zirconia nano-luminescentmaterials, and its luminescent properties have been investigated.ZrO2:Eu3+phosphors were prepared by sol-gel method. Two approaches to chargecompensation effect on the structure and luminescent properties are investigated. The resultshow that these phosphors with different charge compensation are mixed phase of tetragonaland monoclinic phase, and the volume fraction of tetragonal phase of ZrO2:Eu3+/Na+phosphoris bigger than the other phosphors. The phosphor can emits strong red light at606~616nm(5D0â†'7F2) by ultravioled light (395nm) excitated. Compared with two charge compensationpatterns in the ZrO2:Eu3+, it has been found that ZrO2:Eu3+/Na+phosphor show the greatlyluminescence intensity and longer luminescence lifetime of2.497ms.By controlling Eu3+doping concentration, and introduction of Y3+as stable agent,ZrO2:Y3+/Eu3+(YSZ:Eu) nanophosphors with tetragonal structure have been prepared bysol-gel method. The excitation spectra of YSZ:Eu phosphors are mainly attributed toO2-â†'Eu3+charge-transfer (CT) band at about254nm and some sharp lines of Eu3+f-ftransitions in near-UV region with one strong peak at395nm. Under the395nm excitation,intense red emission peaked at607nm corresponding to5D0â†'7F2transition of Eu3+isobserved for6at.%(at.%denotes atomic percentage concentration) YSZ:Eu phosphors as theoptimal doping concentration. The concentration quenching mechanism is electricdipole-electric dipole interaction according to Dexter’s theory. The luminescence propertiessuggest that YSZ:Eu phosphor may be regarded as a potential red phosphor candidate fornear-UV light emitting diodes (LEDs).ZrO2:Y3+/Eu3+/Yb3+(YSZ:Eu/Yb) phosphors with different Yb3+doping concentrationsynthesized via a Pechini sol-gel method. It can be seen that Eu3+4f-4f transition(7F0â†'5D0.1.2.3.4,5L6.7, and5H3) in excitation spectra by monitoring the613nm emission of Eu3+(5D0â†'7F2)and the969nm emission of Yb3+(2F5/2â†'2F7/2). The visible and near-infrared (NIR) emissions in YSZ:Eu/Yb phosphors has been observed by395nm excitated. It is found that it existenergy transfer from Eu3+to Yb3+, the energy transfer process ascribed to the efficient crossrelaxation and cooperative downconversion. Yb3+optimum doping concentration is about11at.%, the hightest energy transfer efficiency has been calculated to be75.11%, thecorresponding quantum efficiency is175.11%. Therefore, the obtained results indicate thatYSZ:Eu/Yb phosphor is a potential candidate for application in the crystalline siliconphotovoltaics.