Dopant and excitation wavelength dependent color tunability in Dy3+:YVO4 and Dy3+/Eu3+:YVO4 microparticles towards white light emission

Abstract

In this study, we investigated the dopant and excitation wavelength color tunability of several Dy³⁺:YVO₄ and Dy³⁺/Eu³⁺:YVO₄ samples with the aim of obtaining white light emission. The materials were prepared in a hydrothermal synthesis in the presence of glycerol and resulted in microsized particles. Although white light can be obtained through choosing an appropriate doping percentage of Dy³⁺ in this material, yet by co-doping appropriate amounts of Dy³⁺ and Eu³⁺ into the YVO₄ matrix a warmer tone of white light (with yellow under tone) can be achieved. Despite the fact that both the as obtained and heat treated materials were of the pure YVO₄ phase when doped they showed differences in their luminescence properties. We show that also by adjusting the excitation wavelength slight changes in the emitted color of the doped and co-doped materials can be obtained. Additionally a detailed analysis of the Dy³⁺/Eu³⁺:YVO₄ co-doped samples revealed that energy is not transferred from the V-O charge transfer band independently to both Eu³⁺ and Dy³⁺ instead a V-O → Dy³⁺ → Eu³⁺ energy transfer takes place. A nonradiative energy transfer between the Dy³⁺ and Eu³⁺ ions is proposed.