Synthesis and optical properties of Eu³⁺ -substituted glaserite-type orthovanadates CsK₂ Y[VO₄ ]₂

A new Eu³⁺ -substituted CsK₂ Y[VO₄ ]₂ glaserite-type orthovanadate phosphor was synthesized by the conventional high temperature solid-state reaction method. The phase purity was confirmed by powder X-ray diffraction study and it reveals that all the compositions crystallize in the hexagonal structure. The morphology and elemental composition were measured by FE-SEM with Energy Dispersive Analysis Of X Rays (EDAX). The band gap is determined by diffuse reflectance spectra. The self-activated luminescence of the host and Eu³⁺ -substituted luminescence behaviours were studied in detail by photoluminescence spectra. The host CsK₂ Y[VO₄ ]₂ shows green emission, whereas the Eu³⁺ -substituted compositions show red emission. Effect of Eu³⁺ concentrations on the photoluminescence behaviour were also been studied. The Eu³⁺ -doped samples show not only several sharp emission lines but also a broad emission band due to presence of the [VO₄ ]^3- in the host, which clearly indicates that there is incomplete energy transfer from (VO₄ ) charge transfer band to Eu³⁺_. The life time of the phosphors also been studied. The Commission Internationale de l'Eclairage (CIE) chromaticity colour coordinates were calculated and it is very much closer to the National Television Standard Committee (NTSC) standards. These investigations evidently reveal that the self-activated and Eu³⁺ -activated phosphors show a great potential applications as a red phosphor for solid-state lighting includes white light-emitting diodes (wLEDs).