Crystal structure and pale-yellow emitting properties of K 3 Gd 1-x Dy x B 6 O 12 solid solutions.

A new potassium dysprosium polyborate, K3 DyB6 O12 , 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 [B5 O10 ]5- groups and Dy3+ and K+ ions. The Fourier transform IR (FT-IR) and ultraviolet-visible (UV-Vis) spectra were investigated. A series of K3 Gd1-x Dyx B6 O12 phosphors was prepared and their photoluminescence properties were studied. The K3 Gd1-x Dyx B6 O12 phosphors exhibit a strong yellow emission band at 577 nm (the 4 F9/2 →6 H13/2 transition of Dy3+ ) under UV excitation of 275 nm (the 8 S7/2 →6 IJ 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 K3 Gd1-x Dyx B6 O12 is a promising pale-yellow emission phosphor for visual displays or solid-state lighting.