A reddish-orange emitting samarium doped α-Na3Y(VO4)2 nanocrystals for single phased UV excitable white light applications

Highlights: • Reddish- orange emitting α-Na₃Y_1-xSm_x(VO₄)₂ nanocrystals for single phase WLED. • Uniform spherical nanocrystals were prepared via solution combustion method. • Host sensitization of Sm³⁺ via broad and intense charge transfer band of vanadate. • High color purity (99.8%) with low CCT (1300 K) suitable for warm white light. • Dipole - dipole interaction among Sm³⁺ result in concentration quenching. -- Abstract: Nanocrystals of samarium doped sodium yttrium vanadate have been synthesized by citrate based solution combustion reaction method for the first time. X-ray powder diffraction analysis and transmission electron microscopic analysis revealed the highly crystalline nature and uniform spherical morphology of the sample. The strong and broad band observed in the UV–Vis absorption spectrum as well as in the photoluminescence excitation spectrum point to the efficient energy transfer from vanadate to Sm³⁺ ion. Under the excitation of near ultraviolet (310 nm), α-Na₃Y_1-xSm_x(VO₄)₂ exhibit reddish orange emission with high purity and the optimal doping concentration of Sm³⁺ ion is found to be about 2 mol %. Unlike mostly reported samarium doped phosphors, red emission (⁴G_5/2 → ⁶H_9/2) is more intense compared to the orange emission (⁴G_5/2 → ⁶H_7/2) in the present system. The main reason for concentration quenching is determined to be dipole-dipole interaction leading to cross relaxation. Strong sensitization of Sm³⁺ ion via host, least chance for re-absorption of blue-green emission due to the weak direct f-f excitation of Sm³⁺ ion and high purity reddish-orange emission suggests samarium doped α-Na₃Y(VO₄)₂ nanocrystal as a potential nanophosphor in the field of single phase white light generation.