Luminescence behavior of Eu 3+ in CaSiO 3:Eu 3+(Bi 3+) and Sr 2SiO 4:Eu 3+(Bi 3+)

Abstract

CaSiO 3:Eu 0.08 3+Bi 0.002 3+ and Sr 2SiO 4:Eu 0.08 3+Bi 0.002 3+ were synthesized by the sol–gel method, and their structure and luminescence characteristics were investigated. The XRD results showed that the symmetry of Sr 2SiO 4:Eu 0.08 3+Bi 0.002 3+ structure, which is similar to the non-close-packing orthogonal structure of K 2SiO 4 is higher than that of CaSiO 3:Eu 0.08 3+Bi 0.002 3+ perovskite structure belonging to the monoclinic system. From the excitation spectra of CaSiO 3:Eu 0.08 3+Bi 0.002 3+and Sr 2SiO 4:Eu 0.08 3+Bi 0.002 3+, it can be seen that the main peaks located at 267 nm, 383 nm, 395 nm, 437 nm, 457 nm and 359 nm, which correspond to the charge transfer band of Eu 3+–O 2−, absorption transition of 7F 0.1– 5G J, 7F 0.1– 5L 6, 7F 1– 5D 3 and 7F 0.1– 5D 2 of Eu 3+ ions and 3P 1– 1S 0 of Bi 3+ ions, respectively. When the CaSiO 3:Eu 0.08 3+Bi 0.002 3+ samples were excited with wavelength of 359 nm, the emission intensity of electronic dipole transition at 609 nm originated from 5D 0– 7F 2 of Eu 3+ ions was stronger than magnetic dipole transition at 587 nm originated from 5D 0– 7F 1 of Eu 3+ ions mainly due to the lower symmetry and the distortion of the structure. However, the opposite situation appeared in the emission spectrum of Sr 2SiO 4:Eu 0.08 3+Bi 0.002 3+. In addition, the intensity comparison of each emission peaks between the emission spectra of CaSiO 3:Eu 0.08 3+Bi 0.002 3+ and Sr 2SiO 4:Eu 0.08 3+Bi 0.002 3+ showed that the energy transfer efficiency between Bi 3+ ions and Eu 3+ ions in Sr 2SiO 4:Eu 0.08 3+Bi 0.002 3+ is apparently higher than that in CaSiO 3:Eu 0.08 3+Bi 0.002 3+.