Crystal structure and pale-yellow emitting properties of K3Gd1–x Dy x B6O12 solid solutions

A new potassium dysprosium polyborate, K3DyB6O12, has been prepared via the high-temperature molten salt method and structurally characterized by single-crystal X-ray diffraction analysis. The structure can be described as a three-dimensional framework com­posed of isolated bicyclic [B5O10]5− groups and Dy3+ and K+ ions. The Fourier transform IR (FT–IR) and ultraviolet–visible (UV–Vis) spectra were investigated. A series of K3Gd1–xDyxB6O12 phosphors was prepared and their photoluminescence properties were studied. The K3Gd1–xDyxB6O12 phosphors exhibit a strong yellow emission band at 577 nm (the 4F9/2→6H13/2 transition of Dy3+) under UV excitation of 275 nm (the 8S7/2→6IJ transition of Gd3+), suggesting the occurrence of the energy transfer Gd3+→Dy3+. The optimized doping concentration of the Dy3+ ion was 8 mol%. We may expect that K3Gd1–xDyxB6O12 is a promising pale-yellow emission phosphor for visual displays or solid-state lighting.