New lanthanide-free self-activated full-color emission phosphor in Y³⁺ doped Sr₃ Bi(VO₄ )₃ system for white light...

Commercially used inorganic phosphors heavily depend on lanthanide doped host materials which are becoming more expensive and also their availability is limited due to scarcity. In this regard, a new lanthanide-free self-activated full-color emission phosphor in Y³⁺ doped Sr₃ Bi(VO₄ )₃ system was developed by the conventional ceramic route. These phosphors crystallize into a hexagonal-type palmierite mineral structure. They exhibit broad excitation bands in the wavelength region of 250-400 nm, owing to the charge transfer transitions from both O^2- and Bi6s² electrons to V⁵⁺ . Upon excitation, these phosphors show bright broad emissions in the 400-750 nm wavelength range, peaking around 535 nm, with a large full width half maximum of 160 nm. The Y substitution allows tuning of the emission from yellowish green to bluish white due to increased distortion of [VO₄ ]^3- tetrahedron. Consequently, the CIE color coordinates changed from (0.42, 0.50) to (0.31, 0.35) which lies in the near-white region in the chromaticity diagram. Thus, the newly developed Y doped Sr₃ Bi(VO₄ )₃ is a promising lanthanide-free full-color emission phosphor for applications in pc-white light emitting diodes.