The Preparation and Luminescence Properties of Gd 2 Sio 5:Tb 3+ @Sio 2  Core-Shell  Spherical Nanoparticles

Abstract

Rare-earth nanoparticles (RE-NPs) are of interest as a type of nanomaterial for biomedical applications such as cancer diagnosis and therapy. Tb3+-doped Gd2SiO5@SiO2 (GSO: Tb3+@SiO2) core-shell NPs with size in the range of 250-350 nm were prepared through coprecipitation and Stöber methods in this study, and SiO2 coating ensured good dispersion and spherical morphology of the NPs. The nanospheres had clear core-shell structure observed by TEM images and EDS spectra. The emission and excitation spectra of the GSO: Tb3+@SiO2 samples were measured, and the cross-relaxation within Tb3+ ions was investigated, and it was demonstrated that the concentration quenching of Tb3+ was caused by electric dipole-quadrupole interaction. Fluorescence decay curves were also measured to study the concentration quenching of Tb3+ and energy transfer (ET) from Gd3+ to Tb3+ ions in the GSO: Tb3+@SiO2 NPs. Moreover, the obtained GSO: Tb3+@SiO2 NPs under X-ray excitation had intensive emission whose spectra match well with the absorption band of the photosensitiser MC540, implying its potential application in X-ray induced photodynamic therapy (X-PDT).

Keywords: Rare-earth, core-shell, photoluminescence, nanospheres