Structure and photoluminescence properties of KSr_4(BO_3)_3:Eu^3+ red-emitting phosphor

We have synthesized a Eu3+-activated KSr4(BO3)3 red phosphor by solid state reactions. Rietveld refinement on X-ray diffraction data indicates that Eu3+ ions are inclined to occupy Sr(2) (8c) site in the structure of KSr4(BO3)3. The composition-optimized KSr4(BO3)3:Eu3+ exhibits a dominant emission peak at 612 nm (5D0-7F2) with CIE coordinates of (0.64, 0.35) under the excitation at 394 nm. By codoping M+ ions (M = Li, Na, and K) in KSr4(BO3)3:Eu3+ to compensate the charge unbalance, the intensities of emission spectra at 612 nm can be increased greatly, but the CIE coordinates will not be changed. The red-emitting KSr4(BO3)3:Eu3+ phosphor may be potential candidate in the fabrication of white light-emitting diodes (LEDs).