Blue-emitting SrB2O4:Eu2+ phosphor with high color purity for near-UV white light-emitting diodes

• Blue phosphor SrB2O4:Eu2+ with CIE coordinate (0.1480, 0.0400) was synthesized.
• This phosphor can be effectively excited from 270 to 350 nm NUV light.
• The optimum doping concentration of Eu2+ ions was found.
• The concentration quenching mechanism of Eu2+ ions was discussed.
• This phosphor features high color purity of 97.0% which is better than BAM:Eu2+.

A blue-emitting SrB2O4:Eu2+ phosphor with high color purity was synthesized by conventional high-temperature solid state reaction method. Its crystal structure, luminescence properties and concentration quenching mechanism were investigated. This phosphor can be effectively excited within the broad near ultraviolet wavelength region from 270 to 350 nm and feature a satisfactory blue-emitting performance.In particular, the color purity of the as-synthesized SrB2O4:Eu2+ phosphor is much better than that of the blue emitting, commercial compound BaMgAl10O7:Eu2+. The emission peaks located at 448 nm, which can be attributed to the transitions of 4f65d1 to 4f7 of Eu2+ ions. It is shown that the 6.0 mol% doping concentration of Eu2+ ions in SrB2O4:Eu2+ phosphor is optimum, and that the concentration quenching occurs when Eu2+ concentration is beyond 6.0 mol%. The physical mechanism of concentration quenching mechanism can be explained by the dipole–dipole interaction of Eu2+ ions, and the critical transfer distance was determined to be 13.98 Å. The present work suggests that the SrB2O4:Eu2+ phosphor is a promising blue-emitting material for near-UV white light-emitting diodes.

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