Eu3+ 이온이 첨가된 Y2(MoO4)3 형광체의 분광학 특성 및 도핑 사이트 연구

Abstract

The luminescence properties of Eu3+ in Y2(MoO4)3 are investigated by optical and laser excitation spectroscopy. The Y2(MoO4)3:Eu3+ phosphors were prepared by solid state reaction method. The excitation and emission spectra and decay curves of Y2(MoO4)3:Eu3+ (0.01 - 100 mol%) were measured at room temperature. The X-ray diffraction (XRD) was used to analyze the structural characteristics of the Y2(MoO4)3:Eu3+ lattices. The charge transfer (CT) band in the wavelength region 250 - 350 nm is observed in the excitation spectra of Eu3+ in Y2(MoO4)3. The excitation lines at 321, 364, 384, 396, 418 and 467 nm are attributed to the 7F0 → 5H7, 7F0 → 5D4, 7F0 → 5L7, 7F0 → 5L6, 7F0 → 5D3 and 7F0 → 5D2 transitions, respectively. The emission spectra of Y2(MoO4)3:Eu3+ under excitation at the CT band and the Eu3+ 5L6 (396 nm) state exhibit the sharp lines in the wavelength region 500-750 nm. The line at around 590 nm is due to the magnetic dipole 5D0 → 7F1 transition and the strongest peak at 615 nm is attributed to the induced electric dipole transition of 5D0 → 7F2. The emission intensity increases with increasing Eu3+-concentration up to 50 mol% and then steep quenching occurs up to 100 mol%. Two lines observed at 578.4 (site A) and 580.4 nm (site B) in the 7F0 → 5D0 excitation spectra correspond to the two different crystallographic sites for Y3+ in Y2(MoO4)3:Eu3+. The luminescence under excitation at two corresponding sites shows single exponential decays with lifetimes of about 0.4 ms. No significant differences in decay curves and emission spectra of Y2(MoO4)3:Eu3+ are observed between site A and site B.