Effect of pH and lattice distortion on the luminescence of (Y,Gd) BO ₃:Eu³⁺ phosphor prepared by the coprecipitation method

(Y,Gd) BO3: Eu3+ phosphor was produced by a coprecipitation method. The morphology of the particles could be controlled by adjustment of the pH value and the heat-treatment method used. The pH value of the coprecipitation solution was a critical parameter for the luminescent properties of the phosphor. The improved chromaticity in smaller or disk-like particles was attributed to higher lattice distortion, which gives rise to the loss of the inversion symmetry at the site of the Eu3+ ion, thus enhancing the D0 5 → F2 7 transition.