Eu 3+ doped in core and shell (YVO 4 :SiO 2 ) nanoparticles show luminescence peaks corresponding to magnetic and electric dipole transitions of Eu 3+ . When Eu 3+ ions occupy Y 3+ sites, Eu 3+ ions are surrounded by eight O 2? ions, which is highly asymmetric ( D 2d ). This asymmetric environment can be used to see amount of Eu 3+ ions present in Y 3+ sites. When Eu 3+ ions are present in shell (SiO 2 ), luminescence intensity is very weak. On further annealing, luminescence intensity increases due to diffusion of Eu 3+ ions towards to YVO 4 core through pores of SiO 2 . Distribution of Eu 3+ in core and shell are supported by lifetime studies. Graphical abstract Decay for 5 D 0 level of Eu 3+ in core (YVO 4 -Eu) and core:shell (YVO 4 -Eu:SiO 2 , YVO 4 :SiO 2 -Eu) annealed at 900°C. Inset shows their lifetime values along with 500°C heated sample. Display Omitted Highlights ? Preparation of highly crystalline YVO 4 nanoparticles covered with SiO 2 at low temperature. ? Luminescence technique could prove the core-shell formation of YVO 4 covered by SiO 2 . ? There are fairly energy transfer both core and core-shell nanoparticles.
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