Synthesis and Optical Properties of a Solid Solution between Boron and Aluminum in NaBa(B9-xAl1-x)O15: Eu2+

Solid state white lighting replaces traditional fluorescent and incandescent lighting due to its higher efficiency and longer lifetimes. One method used to produce solid state white light is combining a near-UV LED with three inorganic phosphors emitting blue, green, and red. The three phosphors incorporated into this device must be efficient with a high photoluminescent quantum yield. NaBaB9O15 was synthesised doped with 3% Eu2+ and determined to have a 95% quantum yield, excellent thermal stability, but emitted a violet-color. NaBaB9O15 has [B3O7]5- units with two triangular structures with one tetrahedral. Aluminum was incorporated into NaBaB9O15 to fill in the tetrahedral units forming a solid solution between boron and aluminum and to shift the emission towards red. 5% and 10% aluminum concentrations were added to NaBa(B1-xAlx)9O15. These were obtained through traditional high temperature solid state synthesis and confirmed as pure by powder x-ray diffraction and subsequent Le’Bail refinement. The volumes of each cell was determined to increase as aluminum increased. Photoluminescent measurements reveal that, when excited with 315 nm NaBaB9O15:Eu2+ is a violet color, NaBa(B0.95Al0.05)9O15:Eu2+ is blue-violet, and NaBa(B0.9Al0.1)9O15:Eu2+ is blue. This indicates that the higher the aluminum concentration, the more red shifted the compound is.Honors CollegeChemistry, Department o