Abstract:

CaSiO₃:Eu³⁺_0.08Bi³⁺_0.002 with a monoclinic perovskite structure was synthesized by using sol-gel method, and its luminescence characteristics were investigated. From the excitation spectrum, it can be seen that the main peaks located at 238, 396, 415, 437 and 359 nm correspond to the charge-transfer band of Eu³⁺—O^2-, the absorption transitions of ⁷F_0,1→⁵L₆, ⁷F₀→⁵D₃, ⁷F₁→⁵D₃ of Eu³⁺ ions, and ³P₁→¹S₀ of Bi³⁺ ions, respectively. When the samples were excited with a light of wavelength 359 or 395 nm, it can be seen from the emission spectrum that the electronic dipole transition located at 609 nm corresponding to ⁵D₀→⁷F₂ of Eu³⁺ ions was stronger than the magnetic dipole transition located at 587 nm corresponding to ⁵D₀→⁷F₁ of Eu³⁺ ions, which shows that more Eu³⁺ ions were located in nonreversion center lattices. The energy transfer from Bi³⁺ ions to Eu³⁺ ions in the phosphor was also discussed. The results show that Eu³⁺ ions could be well sensitized by Bi³⁺ ions, and the energy-transfer pattern between Bi³⁺ ions and Eu³⁺ ions was resonance energy transfer.

Key words: CaSiO₃, Luminescence characteristic, Sensitization, Sol-gel method