Eu3+ 이온이 첨가된 LiMg(PO3)3 형광체의 분광학 특성연구

Abstract

LiMg(PO3)3:Eu3+ phosphors with various Eu3+ concentrations were synthesized by using high-temperature solid-state reaction method. The Eu3+ concentration was 0.1, 1.0, 5.0, 10 and 20 mol % in LiMg(PO3)3. The thermogravimetric (TG) and differential thermal analysis (DTA) were performed for temperature analysis. The crystal structure of the samples was identified by X-ray diffraction (XRD). The XRD patterns were well in accordance with PDF 23-1194 and no obvious impurity phase was observed. Optical properties of the phosphors were investigated by using photoluminescence (PL) spectroscopy and photoluminescence excitation (PLE) spectroscopy. The strong excitation bands due to the ligand to metal-ion charge transfer (C-T) transition of Eu3+ - O2- are observed in the UV region. The strongest excitation line corresponding to the 7F0 → 5L6 transition is observed at 393 nm. All the phosphors, irrespective of Eu3+ ion concentration, show the emissions with strong orange color at 594 nm due to the 5D0 → 7F1 transition and with also strong red color at 615 nm due to the 5D0 → 7F2 transition. The emission peak at 594 nm competes with the peak at 615 nm indicating that site symmetry acting on Eu3+ ion in LiMg(PO3)3 is relatively higher than that in other compounds, e.g. Y2O3:Eu3+. The luminescence intensity of the LiMg(PO3)3:Eu3+ phosphor increases linearly with Eu3+ concentration up to 20 mol %. The decay curves of the Eu3+ emission exhibit no single exponential decay for all the samples (Eu3+ concentration of 0.1 – 20 mol%). This is attributed to the energy transfer between Eu3+ ions or from Eu3+ to quenching site is dominant in the emission processes in LiMg(PO3)3:Eu3+.