KSr4(BO3)3:Pr3+: A new red-emitting phosphor for blue-pumped white light-emitting diodes

Photoluminescence (PL) and photoluminescence excitation (PLE) spectra of KSr4-x(BO3)3: xPr3+ and KSr3.97(BO3)3:0.015Pr3+,0.015Li+.188