In this study,Er^(3+)/Yb^(3+)codoped Y_(2)O_(3)-ZnO ceramic phosphors were prepared by sol-gel method.The samples had two emission bands,namely,green(535 nm) and red(660 nm),which are attributed to Er^(3+):^(2)H_(11/2...In this study,Er^(3+)/Yb^(3+)codoped Y_(2)O_(3)-ZnO ceramic phosphors were prepared by sol-gel method.The samples had two emission bands,namely,green(535 nm) and red(660 nm),which are attributed to Er^(3+):^(2)H_(11/2)(^(4)S_(3/2))→^(4)I_(15/2)and Er^(3+):^(4)F_(9/2)→^(4)I_(15/2)radiative transitions,respectively.The samples exhibited green-and red-emission intensity enhancement by 1.728 and 2.286 times that of the pure Y2O3host,respectively and by 514.468 and 214.341 times that of the pure ZnO host.The emission intensities are first enhanced by lattice expansion.With the change of Y:Zn ratio,the high surface energy is converted into low crystal surface resulting in the change of asymmetry crystal field for matrix.When the intensity of the asymmetric crystal field reaches maximum,both emissions are further boosted.When the high surface energy transforms into crystal surface energy,the microstructure changes into a compact mesoporous structure.Consequently,the chemical stability of the samples improves significantly,and the final emission band of the three samples with mesoporous structures is continuously red.展开更多
Zno.95-xCoo.05CuxO （atomic ratio, x = 0-8%） thin films are fabricated on Si（lll） substrate by reactive magnetron sputtering method. Detailed characterizations indicate that the doped Cu ions substitute the Zn2＋ i...Zno.95-xCoo.05CuxO （atomic ratio, x = 0-8%） thin films are fabricated on Si（lll） substrate by reactive magnetron sputtering method. Detailed characterizations indicate that the doped Cu ions substitute the Zn2＋ ions in ZnO lattice. The doped Cu ions are in ＋1 and ＋2 mixture valent state. The ferromagnetism of the Zno.95-xCoo.o5CuxO film increases gradually with the increase of the Cu＋ ion concentration till x = 6%, but decreases for higher Cu concentration. Experimental results indicate that the increase of ferromagnetism is not owing to the magnetic contribution of Cu＋ ions themselves, but owing to the enhancement of magnetic interaction between Co2＋ ions, which suggests that p-type doping of Cu＋ ions plays an important role in mediating the ferromagnetic coupling between Co ions.展开更多
基金Project supported by the National Natural Science Foundation of China (12104117)Guangdong Basic and Applied Basic Research Foundation (2020A1515010432)Characteristic Innovation Project of Guangdong Provincial Universities 2020 (2020KTXCX077)。
文摘In this study,Er^(3+)/Yb^(3+)codoped Y_(2)O_(3)-ZnO ceramic phosphors were prepared by sol-gel method.The samples had two emission bands,namely,green(535 nm) and red(660 nm),which are attributed to Er^(3+):^(2)H_(11/2)(^(4)S_(3/2))→^(4)I_(15/2)and Er^(3+):^(4)F_(9/2)→^(4)I_(15/2)radiative transitions,respectively.The samples exhibited green-and red-emission intensity enhancement by 1.728 and 2.286 times that of the pure Y2O3host,respectively and by 514.468 and 214.341 times that of the pure ZnO host.The emission intensities are first enhanced by lattice expansion.With the change of Y:Zn ratio,the high surface energy is converted into low crystal surface resulting in the change of asymmetry crystal field for matrix.When the intensity of the asymmetric crystal field reaches maximum,both emissions are further boosted.When the high surface energy transforms into crystal surface energy,the microstructure changes into a compact mesoporous structure.Consequently,the chemical stability of the samples improves significantly,and the final emission band of the three samples with mesoporous structures is continuously red.
基金the Basic Scientific Research Business Expenses of the Central UniversityOpen Project of Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education,Lanzhou University (No.LZUMMM2012001)the Natural Science Foundation of Anhui Province(No.1208085ME84)
文摘Zno.95-xCoo.05CuxO （atomic ratio, x = 0-8%） thin films are fabricated on Si（lll） substrate by reactive magnetron sputtering method. Detailed characterizations indicate that the doped Cu ions substitute the Zn2＋ ions in ZnO lattice. The doped Cu ions are in ＋1 and ＋2 mixture valent state. The ferromagnetism of the Zno.95-xCoo.o5CuxO film increases gradually with the increase of the Cu＋ ion concentration till x = 6%, but decreases for higher Cu concentration. Experimental results indicate that the increase of ferromagnetism is not owing to the magnetic contribution of Cu＋ ions themselves, but owing to the enhancement of magnetic interaction between Co2＋ ions, which suggests that p-type doping of Cu＋ ions plays an important role in mediating the ferromagnetic coupling between Co ions.
