Preparation And Study On Optical Properties Of Pr₆O₁₁ And Yb₂O₃ Doped Yttria-stabilized Zirconia(YSZ) Single Crystals

Rare-earth doped single crystals have great potential applications in solid-state laser devices,biomedicine,lighting and color display.The development of blue light emitting diode(BLED)provides a better prospect for Pr³⁺doped materials,especially crystals,which can absorb blue light.Yttrium oxide stabilized zirconia(YSZ)single crystal is an ideal choice for optical matrix materials because of its green,pollution-free,low phonon energy and excellent physical and chemical properties.Based on these,this thesis carried out the following research:(1)A series of high quality Pr³⁺doped YSZ single crystals with different concentrations of Pr₆O₁₁ were grown by optical floating region method.The phase structure and optical properties of these crystals were studied.The results of XRD and Raman spectra show that all the crystal samples are cubic phase,and the lattice constant increases with the increase of doping concentration.XPS and EPR analysis showed that praseodymium existed in the YSZ lattice as Pr³⁺in both single crystal and ceramic samples.The results of absorption spectra and the PLE test at 614 nm measured at room temperature indicate that the Pr³⁺doped YSZ single crystal has a strong absorption of blue light in the range of450-480 nm and can be effectively pumped by it.The PL of Pr³⁺doped YSZ crystals at 565 nm,588 nm,614 nm,638 nm and 716 nm were measured under the excitation of 450 nm source.With the increase of doping concentration,the luminescence intensity first increases and then decreases,and the calculation shows that the dipole-dipole interaction is the main mechanism of energy transfer in the concentration quenching.The color coordinates of the luminous spectrum of the sample were accurately described by CIE software,and the color purity of the sample in the red and orange light region was calculated to reach 98.9%.(2)On the basis of Pr³⁺doped YSZ single crystal,Yb³⁺/Pr³⁺co-doped YSZ single crystal with different Yb₂O₃ concentration was prepared to improve its infrared absorption capacity and achieve up-conversion luminescence,and its structure and optical properties were studied.The results of XRD and Raman show that all crystal samples are cubic phase structure,and the lattice constant increases first and then decreases with the increase of doping concentration.The results of transmission spectra show that the transmittance of the crystals in the visible region is?90%.The up-conversion PL results under 980 nm laser excitation show that the addition of Yb³⁺makes the crystal material realize effective up-conversion emission,and several emission peaks with 448 nm,508nm,617 nm and 656 nm as the center are observed,respectively.With the increase of Yb³⁺doping concentration,the luminescence intensity of the sample first increased and then decreased,and the optimal doping concentration was 2.5mol%.The results show that the fluorescence lifetime of the ³P₁+¹I₆?³H₅transition at 541 nm reaches 207.785?s,which is expected to be used in laser and fluorescence output.Finally,CIE software was used to accurately depict the color coordinates of the luminous spectrum of the sample,and the color purity was calculated to be 69.86%.