Structural and photoluminescent properties of nanosized BaMgAl10O17:Eu2+ blue-emitting phosphors prepared by sol-gel method

Hao Van Bui, Tu Nguyen, Manh Cuong Nguyen, Trong An Tran, Ha Le Tien, Hao Tam Tong, Thi Kim Lien Nguyen and Thanh Huy Pham

Abstract

We report on the photoluminescent properties of Ba_0.9Eu_0.1MgAl₁₀O₁₇ (BAM) phosphors in correlation with the host crystalline structures. The phosphors were synthesized by citrate sol-gel process, followed by a sintering and a reduction step, both at elevated temperatures. We found that the phosphors were amorphous when sintered at temperatures below 900 °C. At 1000 °C, the crystalline structure was mainly that of BaAl₂O₄ phase. The BaMgAl₁₀O₁₇ phase appeared at 1100 °C, and became dominant with increasing temperature. At 1300 °C, the BaAl₂O₄phase almost disappeared, and only BaMgAl₁₀O₁₇ features were found. The luminescent characteristics of the phosphors were closely related to the structures of the host lattice. Under the same reduction conditions, the phosphors sintered at 1000 °C showed the emission of both Eu³⁺and Eu²⁺. For the phosphors sintered at higher temperatures, the main features were originated from the emission of Eu²⁺. We additionally observed the increase of emission intensity and the broadening of emission spectra with increasing reduction temperature