Phosphor of KMgF3：Ce^3＋ is synthesized through solvothermal method at 180 ℃ and characterized by means of X-ray powder diffraction （XRD） and environment scanning electron microscopy （ESEM）. X-ray photoelectron ...Phosphor of KMgF3：Ce^3＋ is synthesized through solvothermal method at 180 ℃ and characterized by means of X-ray powder diffraction （XRD） and environment scanning electron microscopy （ESEM）. X-ray photoelectron spectroscopy （XPS） is applied to the study of the energy band structure of KMgF3：Ce^3＋ and confirms the oxygen content of the product is very low. The fluorescence spectra of the rare-earth ion-doped KMgF3 is investigated by the fluorescence spectrophotometer. In the emission spectra, there is a broadband emission with a maximum center located at 306 nm arising from d-f transition of Ce^3＋ in the host. This will be useful for ultraviolet tunable lasers.展开更多
Nanocrystals and powders of KMgF3 doped with Eu^2＋ were synthesized by the microemulsion method and the selvothermal process, respectively. The emission and excitation spectra of KMgF3： Eu^2＋ phosphors were measure...Nanocrystals and powders of KMgF3 doped with Eu^2＋ were synthesized by the microemulsion method and the selvothermal process, respectively. The emission and excitation spectra of KMgF3： Eu^2＋ phosphors were measured and compared with those of the samples synthesized through a solid state reaction, Bridgman-Stockbarger method, and mild hydrothermal technique. The KMgF3： Eu^2＋ samples synthesized by means of the microemulsion method and the solvothermal process show only a sharp emission peak located at 360 nm in the emission spectra, which arises from the f→f（ ^6P7/2→^8S7/2 ） transition of Eu^2＋ The broad emission bands appear at 420 nm, which arises from Eu^2＋←O^2- cannot be observed（ in the mild hydrothermal and single crystal samples, the emission peak at 420 nm besides the emission of Eu^2＋ at 360 nm is observed）. In the excitation spectrum of the KMgF3 ： Eu^2＋ samples synthesized by the microemulsion method and the solvothermal process, the excitation peaks show an intensive blue shift. The blue shift can be attributed to the lower oxygenic content in the KMgF3 ： Eu^2＋ samples synthesized by the microemulsion method and the selvothermal process.展开更多
Lanthanide(Ln^(3+))-doped photon avalanche(PA)upconversion nanoparticles(UCNPs)have great prospects in many frontier applications,such as super-resolution bioimaging,miniaturized lasers,single-molecule tracking,and qu...Lanthanide(Ln^(3+))-doped photon avalanche(PA)upconversion nanoparticles(UCNPs)have great prospects in many frontier applications,such as super-resolution bioimaging,miniaturized lasers,single-molecule tracking,and quantum optics.However,it remains challenging to realize PA in colloidal Ln^(3+)-doped UCNPs at room temperature(RT),due to the deleterious quenching effect associated with the surface and lattice OH^(-)defects.展开更多
基金supported by the National Natural Science Foundation of China(No.50702057).
文摘Phosphor of KMgF3：Ce^3＋ is synthesized through solvothermal method at 180 ℃ and characterized by means of X-ray powder diffraction （XRD） and environment scanning electron microscopy （ESEM）. X-ray photoelectron spectroscopy （XPS） is applied to the study of the energy band structure of KMgF3：Ce^3＋ and confirms the oxygen content of the product is very low. The fluorescence spectra of the rare-earth ion-doped KMgF3 is investigated by the fluorescence spectrophotometer. In the emission spectra, there is a broadband emission with a maximum center located at 306 nm arising from d-f transition of Ce^3＋ in the host. This will be useful for ultraviolet tunable lasers.
基金Supported by the National Natural Science Foundation of China(No. 90201032) and the Postdoctoral Fund of Dalian Nationali-ties University(No. 20056110)
文摘Nanocrystals and powders of KMgF3 doped with Eu^2＋ were synthesized by the microemulsion method and the selvothermal process, respectively. The emission and excitation spectra of KMgF3： Eu^2＋ phosphors were measured and compared with those of the samples synthesized through a solid state reaction, Bridgman-Stockbarger method, and mild hydrothermal technique. The KMgF3： Eu^2＋ samples synthesized by means of the microemulsion method and the solvothermal process show only a sharp emission peak located at 360 nm in the emission spectra, which arises from the f→f（ ^6P7/2→^8S7/2 ） transition of Eu^2＋ The broad emission bands appear at 420 nm, which arises from Eu^2＋←O^2- cannot be observed（ in the mild hydrothermal and single crystal samples, the emission peak at 420 nm besides the emission of Eu^2＋ at 360 nm is observed）. In the excitation spectrum of the KMgF3 ： Eu^2＋ samples synthesized by the microemulsion method and the solvothermal process, the excitation peaks show an intensive blue shift. The blue shift can be attributed to the lower oxygenic content in the KMgF3 ： Eu^2＋ samples synthesized by the microemulsion method and the selvothermal process.
文摘Lanthanide(Ln^(3+))-doped photon avalanche(PA)upconversion nanoparticles(UCNPs)have great prospects in many frontier applications,such as super-resolution bioimaging,miniaturized lasers,single-molecule tracking,and quantum optics.However,it remains challenging to realize PA in colloidal Ln^(3+)-doped UCNPs at room temperature(RT),due to the deleterious quenching effect associated with the surface and lattice OH^(-)defects.
