Synthesis and luminescence properties of novel LiSr4(BO3)3:Dy3+ phosphors

The LiSr4(BO3)3:Dy3+ phosphors were synthesized in air by solid-state reaction route. The as-synthesized phosphors were characterized by X-ray powder diffraction (XRD), photoluminescence excitation (PLE) and photoluminescence (PL) spectra. The PLE spectra show the excitation peaks from 300 to 400 nm is due to the 4f–4f transitions of Dy3+. This mercury-free excitation is useful for solid state lighting and light-emitting diodes (LEDs). The emission of Dy3+ ions upon 350 nm excitation is observed at 481 nm (blue) due to the 4F9/2→6H15/2 transitions, and 575 nm (yellow) due to 4F9/2→6H13/2 transitions. The optimal PL intensity of the LiSr4(BO3)3:Dy3+ phosphors under 350 nm excitation is found to be at the concentration of x=0.02 and the synthesis temperature at 1000 °C. The CIE chromaticity coordinates for LiSr4(BO3)3:Dy3+ phosphors are simulated and located in the bluish-white region. All the results imply that the studied LiSr4(BO3)3:Dy3+ phosphors could be potentially used as white LEDs.