The structure and properties of CeO2 surfaces have been intensively studied due to their importance in a lot of surface-related applications. Since most of surface techniques probe the structure information inside the...The structure and properties of CeO2 surfaces have been intensively studied due to their importance in a lot of surface-related applications. Since most of surface techniques probe the structure information inside the outermost surface plane, the subsurface structure information has been elusive in many studies. Using the profile imaging with aberration-corrected transmission electron microscopy, the structure information in both the outermost layer and the sublayers of the CeO2（100） surface has been obtained. In addition to the normal structures that have been reported before, where the surface is Ce-or O-terminated, a metastable surface has been discovered. In the new structure, there is an atomic layer reversal between the outermost layer and the sublayer, giving a structure with O as the outermost layer for the stoichiometry of normal Ce-terminated surface. The charge redistribution for the polarity compensation has also been changed relative to the normal surface.展开更多
The Ce^3＋and Dy3＋ co-doped fluorosilicate glass and glass ceramics containing SrF2 or CeF3 nanocrystals were prepared under reducing atmosphere. The precipitated nano-crystalline phase shifted from cubic SrF2 to hex...The Ce^3＋and Dy3＋ co-doped fluorosilicate glass and glass ceramics containing SrF2 or CeF3 nanocrystals were prepared under reducing atmosphere. The precipitated nano-crystalline phase shifted from cubic SrF2 to hexagonal CeF3 gradually with the heat treatment temperature increasing flom 620 to 680 ℃. The glass and glass ceramics emitted white light, deriving from a combination of the Ce3＋ blue and the Dy3＋ yellow light. The CIE coordinates could be tuned by adjusting the ratio of Ce3＋/Dy3＋ concentration. The luminescence could be enhanced significantly by annealing the samples at the temperatures lower than 640℃.展开更多
基金supported by the National natural Science Foundation of China(51525102,51390475,51371102 and 21673277)the National Basic Research Program of China(2015CB654902)
文摘The structure and properties of CeO2 surfaces have been intensively studied due to their importance in a lot of surface-related applications. Since most of surface techniques probe the structure information inside the outermost surface plane, the subsurface structure information has been elusive in many studies. Using the profile imaging with aberration-corrected transmission electron microscopy, the structure information in both the outermost layer and the sublayers of the CeO2（100） surface has been obtained. In addition to the normal structures that have been reported before, where the surface is Ce-or O-terminated, a metastable surface has been discovered. In the new structure, there is an atomic layer reversal between the outermost layer and the sublayer, giving a structure with O as the outermost layer for the stoichiometry of normal Ce-terminated surface. The charge redistribution for the polarity compensation has also been changed relative to the normal surface.
基金Project supported by National Natural Science Foundation of China (50902120)the Research Fund of the Doctoral Program of Higher Education of China (20100101120025)+1 种基金the Science and Technology Innovative Research Team of Zhejiang Province (2009 R50010)Program for Changjiang Scholars and Innovative Research Team in University
文摘The Ce^3＋and Dy3＋ co-doped fluorosilicate glass and glass ceramics containing SrF2 or CeF3 nanocrystals were prepared under reducing atmosphere. The precipitated nano-crystalline phase shifted from cubic SrF2 to hexagonal CeF3 gradually with the heat treatment temperature increasing flom 620 to 680 ℃. The glass and glass ceramics emitted white light, deriving from a combination of the Ce3＋ blue and the Dy3＋ yellow light. The CIE coordinates could be tuned by adjusting the ratio of Ce3＋/Dy3＋ concentration. The luminescence could be enhanced significantly by annealing the samples at the temperatures lower than 640℃.
