[Preparation of CeO2 : Eu3+ powders by sol-gel method and their photoluminescence properties].
CeO2 Eu3+ phosphor powders with various Eu3+ concentrations have been prepared by the sol-gel method. Upon excitation with UV light, the CeO2 : Eu3+ powders showed bright orange red emissions due to the 4f-4f transitions of Eu3+ ions. X-ray diffraction (XRD), TG-DTA and Photoluminescence (PL) measurements were used to characterize the samples. XRD analysis showed that the powders with pure cubic fluorite-type CeO2 phase at an up to 10at. % concentration of Eu3+ was obtained at the sintering temperatures from 500 to 1 250 degrees C. The large solubility for doping Eu3+ ions in CeO2 is due to the nearness of ionic radius between Ce4+ and Eu3+. It was also found that an increase in sintering temperature promotes the grain growth of CeO2 and improves its crystallinity. The excitation spectra of the CeO2 : Eu3+ powders were dominated by a broad band at 300-390 nm, suggesting the efficient energy transfer from the O(2-) - Ce4+ charge-transfer state to the doping Eu3+ in the CeO2 : Eu3+ powders. The CeO2 : Eu3+ phosphor powders with a 6at. % concentration o f Eu3+ sintered at 1 250 degrees C revealed the strongest photoluminescence and then in abruptly decreased with increasing the doping concentration indicating the concentration quenching. The mechanism of concentration quenching could be explained as the result of the dipole-quadrupole interaction of neighboring Eu3+.
Wang
Xiao-Dong
XD
Physics Department, Shantou University, Shantou 515063, China.
Liu
Xiao-Hua
XH
Chen
Shao-Jun
SJ
Li
Ming
M
Liu
Min
M