The single crystal growth of stoichiometric host luminescent crystal Na_5Eu(WO_4)_4 has been investigated. Using Na_2WO_4 as a flux,the optimum conditions to grow a pure single crystal by flux-slow-cooling method have...The single crystal growth of stoichiometric host luminescent crystal Na_5Eu(WO_4)_4 has been investigated. Using Na_2WO_4 as a flux,the optimum conditions to grow a pure single crystal by flux-slow-cooling method have been determined.A high optical quality single crystal of dimention 4.5 mm has been grown,which is the largest one as we know so far.The micro-hardness of Na_5Eu(WO_4)_4 single crystal is 3.46×10~3 MPa.Its refractive index is 1.81 in white light wavelength region and the specific gravity is 5.65 g/cm^3.The fluorescent and excitation spectra have been determined and the reason of the fluorescent quench of ~5D_2 and ~5D_1 to ~7F_j of Eu^(3+)can be explained as multi-phonon non-radiation transition.展开更多
Tetragonal structure La1-xBixOCl polycrystals were prepared by solid state synthesis. With increase in bismuth content, the morphology of the prepared samples changed from non-oriented particles to layered crystals an...Tetragonal structure La1-xBixOCl polycrystals were prepared by solid state synthesis. With increase in bismuth content, the morphology of the prepared samples changed from non-oriented particles to layered crystals and the broadband blue-white emission from LaOCl polycrystals decreased dramatically. Comparative experiments and X-ray photoelectron spectroscopy（XPS） analysis indicated that the host emission more possibly originated from Cl self-doping in oxychloride crystals. According to a close composition relationship of the Cl self-doping behavior and crystal morphology, it was suggested that the La composition strengthened the interlayer interaction between Cl^– anion and crystal cell lamellar, hindering the orientation of LaOCl crystals. The results of our work would deepen the understanding of the orientation structure of tetragonal oxyhalides and offer an insight into the origin of its host luminescence.展开更多
文摘The single crystal growth of stoichiometric host luminescent crystal Na_5Eu(WO_4)_4 has been investigated. Using Na_2WO_4 as a flux,the optimum conditions to grow a pure single crystal by flux-slow-cooling method have been determined.A high optical quality single crystal of dimention 4.5 mm has been grown,which is the largest one as we know so far.The micro-hardness of Na_5Eu(WO_4)_4 single crystal is 3.46×10~3 MPa.Its refractive index is 1.81 in white light wavelength region and the specific gravity is 5.65 g/cm^3.The fluorescent and excitation spectra have been determined and the reason of the fluorescent quench of ~5D_2 and ~5D_1 to ~7F_j of Eu^(3+)can be explained as multi-phonon non-radiation transition.
基金Project supported by the National Natural Science Foundation of China(61465006,61265007)Reserve Talents Project of Yunnan Province(2015HB013)
文摘Tetragonal structure La1-xBixOCl polycrystals were prepared by solid state synthesis. With increase in bismuth content, the morphology of the prepared samples changed from non-oriented particles to layered crystals and the broadband blue-white emission from LaOCl polycrystals decreased dramatically. Comparative experiments and X-ray photoelectron spectroscopy（XPS） analysis indicated that the host emission more possibly originated from Cl self-doping in oxychloride crystals. According to a close composition relationship of the Cl self-doping behavior and crystal morphology, it was suggested that the La composition strengthened the interlayer interaction between Cl^– anion and crystal cell lamellar, hindering the orientation of LaOCl crystals. The results of our work would deepen the understanding of the orientation structure of tetragonal oxyhalides and offer an insight into the origin of its host luminescence.
