Preparation and characteristics of core–shell structure Y3Al5O12:Yb3+@SiO2 nanoparticles

The club-shape (Y0.98Yb0.02)3Al5O12 nanoparticles (YAG:Yb3+), which were synthesized by the co-precipitation method, had been successfully coated with silica from hydrolysis and condensation of tetraethyl orthosilicate (TEOS). The thickness of SiO2 shell can be tuned by the amount of TEOS. The influence of different modifying surfactants, polyvinylpyrrolidone (PVP), polyethylene glycol (PEG) and cetyltrimethyl ammonium bromide (CTAB), on the final product had been investigated. The morphology and structure of the nanoparticles were characterized by scanning electron microscopy (SEM) and transmission electronic microscopy (TEM). Surface composition of the samples was studied by X-ray photoelectron spectroscopy (XPS). The results show that PVP is much more beneficial to the dispersion and formation of the core–shell structure than the others. The near-infrared photoluminescence emissions of the nanoparticles were also investigated under the excitation of 940 nm laser diode. The results indicate that SiO2 shell can increase the luminescence intensity and lifetime of YAG:Yb3+ in the near infrared region emissions because the shell can reduce OH group content adsorbed on the surface of the samples.

► Core–shell YAG:Yb3+@SiO2 was obtained.
► PVP surfactant is more benefit to coat SiO2 on YAG surface.
► Core–shell structure increases emission intensity and lifetime of Yb3+ by decreasing surface defects.
► SiO2 shell thickness influences the PL properties of YAG:Yb3+.
► XPS determination indicated SiO2 shell can reduce the content of OH group on the surface of YAG.