Preparation And Optical Properties Of Yttria Stabilized Zirconia Single Crystals Doped With Dy₂O₃ And Tm₂O₃

Yttria-stabilized zirconia(YSZ)can be selected as the suitable host of laser materials because of its high refractive index and low optical loss.In order to prepare excellent performance light-emitting crystals that can be used for yellow lasers and high-efficiency white light output.In this paper,The host YSZ single crystals,YSZ:xDy₂O₃ single crystals doped with different concentrations of Dy₂O₃,and YSZ:xDy/Tm single crystals co-doped with different concentrations of Dy₂O₃ and 0.5 mol%Tm₂O₃ were further prepared by the optical floating zone method.The single crystal microstructure and optical properties were characterized and tested in detail,and its potential applications in the field of yellow lasers and white LEDs were evaluated.1.The polycrystalline ceramic rods required for crystal growth were synthesized by the solid-phase reaction method.XRD results showed that the ceramic samples are a mixed phase of monoclinic and cubic phases.The single crystals are further prepared by the optical floating zone method,and investigated systematically the microstructures of single crystals,XRD and Raman results show that that all samples have single cubic zirconia structure.2.In the range of 240-900 nm,the UV-visible absorption spectra of YSZ:xDy₂O₃ and YSZ:xDy/Tm single crystals mainly show the absorption peaks of Dy³⁺and Tm³⁺.Among them,the absorption peak with a wavelength of 349 nm has a strong intensity,which can be used as the excitation wavelength of YSZ:xDy₂O₃ and YSZ:xDy/Tm single crystals.3.Under the excitation of 349 nm,the emission spectrum of YSZ:xDy₂O₃single crystal has emission peaks at 483 nm,584 nm,680 nm and 767 nm,which correspond to the energy level transition of Dy³⁺from ⁴F_9/2?⁶H_J/2(J=15,13,11 and 9),respectively.The intensity of the yellow emission peak at 584 nm is the strongest,followed by the intensity of the blue emission peak at 483 nm.When the doping concentration of Dy₂O₃ is 0.5 mol%,the highest yellow light emission intensity is obtained.The fluorescence lifetime of YSZ:xDy₂O₃samples was measured.Due to the interaction among Dy³⁺ions,the lifetime decay curves of ⁴F_9/2?⁶H_13/2 and ⁴F_9/2?⁶H_15/2 decreased significantly with the increase of Dy₂O₃ concentration.The chromaticity coordinates(CIE)of YSZ:xDy₂O₃ samples are about(0.54,0.45),which indicates an orange-yellow emission light.The results show that YSZ single crystals doped by Dy₂O₃ can be used as a yellow laser.4.Under the excitation of 349 nm,the emission spectrum of YSZ:xDy/Tm single crystal showed emission peaks at 458 nm,483 nm and 584 nm.Among them,458 nm corresponds to the Tm³⁺(¹D₂?³F₄)transition;483 nm and 584nm correspond to the Dy³⁺(⁴F_9/2?⁶H_13/2)transition.Due to the resonance energy transfer between Tm³⁺and Dy³⁺ions,the energy absorbed by Tm³⁺can be used to excite Dy³⁺.Therefore,the intensity of the emission peak of Tm³⁺gradually decreases with the increase of the concentration of Dy₂O₃,and the fluorescence decay time of the corresponding Tm³⁺energy level transition at 458 nm also gradually decreases.The intensity of the emission peak of Dy³⁺increases first(the strongest when x=0.75)and then decreases.When x=0.75,the standard white light color coordinate value(0.33,0.33)is obtained,which shows its application value in the field of near-ultraviolet excited white light LEDs.