Synthesis of High-Brightness Blue-Emitting Phosphors Sr2MgSi2O7:Eu2+, Er3+ by Gel-Combustion Method Assisted by Microwave and their Properties

Abstract

High-brightness blue emitting phosphors Sr₂MgSi₂O₇:Eu²⁺, Er³⁺ were synthesized successfully by gel-combustion method assisted by microwave. The as-synthesized phosphors were analyzed and characterized by X-ray diffraction and fluorescence spectrophotometer. The influences of co-doped Er³⁺ concentration, fuel urea and flux H₃BO₃ on luminescent properties of samples were investigated. The results show that Sr₂MgSi₂O₇: Eu²⁺, Er³⁺ phosphors possess the tetragonal crystal structure similar to that of Sr₂MgSi₂O₇. The excitation spectrum shows a broad band from 250 to 450 nm and the strongest excitation peak is at 358 nm. The emission spectrum excited by 358 nm also shows a wide band with the main peak at ca. 467 nm, which is ascribed to the typical transition from 4f⁶5d¹ to 4f⁷ of Eu²⁺. It is found that co-doped Er³⁺ can sensitize effectively the luminescence of Eu²⁺ ions in Sr₂MgSi₂O₇ host. The luminescence intensity reaches the strongest when the concentration of co-doped Er³⁺ is 0.01, the mass ratio of urea to nitrate is 1.5:1 and the mole fraction of H₃BO₃ is 15 % and it is about 1.3 times of single-doped Eu²⁺ sample.