Synthesis and characteristics of nano-size sandwich structure (Y,Gd)BO3: Eu3+ phosphors

► Sandwich structure of core-shell-shell SiO2@(Y,Gd)BO3:Eu3+@SiO2 spheres are obtained. ► Core-shell structure affects the crystal field surrounding of Eu3+ in (Y,Gd)BO3:Eu3+. ► Core-shell-shell phosphors increased emission intensity by decreasing surface defects. ► R/O value and chromaticity coordinates shifted to red in the core-shell-shell structure.