Melt synthesis of Eu-doped oxide phosphors using arc-imaging furnace

To synthesize various complex oxide materials and their solid solutions, we applied a novel “melt-synthesis technique” rather than conventional solid-state reaction techniques. Rapid synthesis methods to develop those double oxides have been strongly anticipated. During melt synthesis, the mixture of oxides or their precursors is melted rapidly (1–60 s) in an arc-imaging furnace using strong light radiation. A spherical molten sample with multiple homogeneously mixed cations was solidified directly on a copper hearth with rapid cooling of ca. 102 °C/s.We studied the synthesis of A2BO4 type double oxides (AA′)2BO4 (A = Sr2+, Ca2+, A′ = La3+, Gd3+, Y3+, Eu3+, B = Al) using this method. Homogeneous samples with Eu3+ dopants were synthesized using liquid phase mixing in a few seconds, which is much faster than diffusions of ions in solid phase. Red fluorescence under the irradiation of ultraviolet light (254 and 365 nm) was observed. The excitation band shifted.