Synthesis and optical properties of Eu -substituted glaserite-type orthovanadates CsK Y[VO ].

A new Eu -substituted CsK Y[VO ] 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 Eu -substituted luminescence behaviours were studied in detail by photoluminescence spectra. The host CsK Y[VO ] shows green emission, whereas the Eu -substituted compositions show red emission. Effect of Eu concentrations on the photoluminescence behaviour were also been studied. The Eu -doped samples show not only several sharp emission lines but also a broad emission band due to presence of the [VO ] in the host, which clearly indicates that there is incomplete energy transfer from (VO ) charge transfer band to Eu 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 Eu -activated phosphors show a great potential applications as a red phosphor for solid-state lighting includes white light-emitting diodes (wLEDs).