Lanthanides(Ln^(3+))doped luminescent materials play critical roles in lighting and display techniques.While increasing experimental and theoretical research have been carried out on aluminate-based phosphors for whit...Lanthanides(Ln^(3+))doped luminescent materials play critical roles in lighting and display techniques.While increasing experimental and theoretical research have been carried out on aluminate-based phosphors for white light-emitting diodes(WLEDs)over the past decades,most investigation was mainly focused on their luminescent properties;therefore,the local structure of the light emission center remains unclear.Especially,doping-induced local composition and structure modification around the luminescent centers have yet to be unveiled.In this study,we use advanced electron microscopy techniques including electron diffraction(ED),high-resolution transmission electron microscopy(HRTEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM),in combination with energy dispersive X-ray spectroscopy(EDX)and electron energy loss spectroscopy(EELS),to reveal atomically resolved crystalline and chemical structure of Ce^(3+)doped CaYAlO4.The microscopic results prove substantial microstructural and compositional inhomogeneities in Ce^(3+)doped CaYAlO_(4),especially the appearance of Ce dopant clustering and Ce^(3+)/Ce^(4+)valence variation.Our research provides a new understanding the structure of Ln^(3+)doped luminescent materials and will facilitate the materials design for next-generation WLEDs luminescent materials.展开更多
基金funded by the National Natural Science Foundation of China(Nos.52002357,22105175,and 51932009)P.L.acknowledges the financial support from the Carlsberg Foundation(No.CF20-0612).
文摘Lanthanides(Ln^(3+))doped luminescent materials play critical roles in lighting and display techniques.While increasing experimental and theoretical research have been carried out on aluminate-based phosphors for white light-emitting diodes(WLEDs)over the past decades,most investigation was mainly focused on their luminescent properties;therefore,the local structure of the light emission center remains unclear.Especially,doping-induced local composition and structure modification around the luminescent centers have yet to be unveiled.In this study,we use advanced electron microscopy techniques including electron diffraction(ED),high-resolution transmission electron microscopy(HRTEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM),in combination with energy dispersive X-ray spectroscopy(EDX)and electron energy loss spectroscopy(EELS),to reveal atomically resolved crystalline and chemical structure of Ce^(3+)doped CaYAlO4.The microscopic results prove substantial microstructural and compositional inhomogeneities in Ce^(3+)doped CaYAlO_(4),especially the appearance of Ce dopant clustering and Ce^(3+)/Ce^(4+)valence variation.Our research provides a new understanding the structure of Ln^(3+)doped luminescent materials and will facilitate the materials design for next-generation WLEDs luminescent materials.
