Studies On Luminescence Properties Of Rare Earth Ions Doped High Density Germanate Glasses And Oxyfluoride Glass Ceramics

Germanate glass has excellent glass forming properties,excellent physical and chemical properties,high transmittance in visible region,good solubility and dispersion ability of rare earth ions.At the same time,compared with the currently mature silicate scintillating glass,germanate glass has lower phonon energy,which can reduce the nonradiative relaxation and show better scintillation properties.In this thesis,germanate glass was used as glass matrix,and two aspects were studied.The first was that different rare earth ions doped high density germanate glasses were prepared and the thermal stability and the luminescent properties of rare earth ions were studied by differential thermal analysis,transmission spectra,fluorescence spectra,X-ray excitation spectra and fluorescence decay.The second was that rare earth doped germanate glass ceramics containing fluoride nanocrystals were prepared and the thermal properties,controlled precipitation of nanocrystals,luminescent properties of rare earth ions were studied by differential thermal analysis,X-ray diffraction,transmission electron microscopy,transmission spectra,fluorescence spectra,X-ray excited spectra.Eu³⁺singly doped transparent high density germanate glasses were prepared.The results show that the densities of all glasses exceeded 6.5g/cm³,and the high density requirement for scintillating glass is achieved.The glass has good thermal stability and high transmittance of visible light.All of the glasses emit strong red light with the excitations of 393 nm light and X-ray.At the same time,there is the possible energy transfer from Gd³⁺to Eu³⁺ions,which could promote the red light emission of Eu³⁺.Tb³⁺singly doped transparent high density germanate glasses were prepared.The results show that the glass has good stability and is not easy to crystals precipitation.All the glass densities are exceeded 6.3g/cm³,and the demand for high density of scintillating glass is achieved.Under the excitations of 377 nm light and X-ray,the glass emit intense green light.The energy transfer from Gd³⁺to Eu³⁺ions may promote the green light emission of Tb³⁺.Thus it can be as a potential glass scintillation material.Ce³⁺singly doped transparent high density germanate glasses were prepared.The reduction of Ce³⁺is successful in weak reduction atmosphere.The results show that all the glass densities is more than 6.4g/cm³⁺,and the physical properties of glass are better.The fluorescence lifetime of Ce³⁺in the range from 10.44ns to 32.09ns,and fast luminescence attenuation makes glass hopeful for rapid event detection.Pr³⁺singly doped transparent high density germanate glasses were prepared.The results show that the densities of all glasses exceeded 6.5g/cm³,and the glasses have excellent thermal stability.Under the excitation of 449 nm light,the glasses emit intense orange light.The fluorescence lifetime of Pr³⁺is only a dozen microseconds,which has favorable research significance in scintillation materials.Ce³⁺singly doped transparent oxyfluoride germanate glass ceramics containing LaF₃ nanocrystals were prepared.The results show that cerium exist mainly in the form of Ce³⁺in weak reduction atmosphere,and glass ceramics containing LaF₃nanocrystals still have high transmittance.The luminescence of glass ceramics is obviously enhanced,and the intensity of the luminescence increases with the increasing size of nanocrystals.Eu³⁺singly doped transparent oxyfluoride germanate glass ceramics containing LaF₃ nanocrystals were prepared.The results show that glass ceramics emit strong red light with the excitations of 393 nm light and X-ray.The glass ceramics retain high transparency and obviously enhance the luminescence of Eu³⁺,which can be used as a potential red scintillation material.