Highly Uniform Hollow GdF₃ Spheres: Controllable Synthesis, Tuned Luminescence, and Drug-Release Properties

Abstract

In this paper, uniform hollow mesoporous GdF3 micro/nanospheres were successfully prepared by a facile two-step synthesis route without using any surfactant, catalyst, and further calcination process. The precursor Gd(OH)CO3 spheres are prepared by a coprecipitation process. After that, uniform and size-tunable GdF3 hollow spheres were easily coprecipitated with NaBF4 at the sacrifice of the precursor with low temperature and short reaction time. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution TEM, N2 adsorption/desorption, and up-conversion (UC) photoluminescence spectra were used to characterize the as-obtained products. It is found that the initial pH value and NaBF4/Gd(3+) molar ratios play important roles in the structures, sizes, and phases of the hollow products. The growth mechanism of the hollow spheres has been systematically investigated based on the Kirkendall effect. Under 980 nm IR laser excitation, UC luminescence of the as-prepared Yb(3+)/Er(3+)-codoped GdF3 hollow spheres can be changed by a simple adjustment of the concentration of the Yb(3+) ion. Enhanced red emission is obtained by introducing Li(+) ions in GdF3:Yb(3+)/Er(3+). Furthermore, a doxorubicin release experiment and a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide cytotoxicity assay reveal that the product has potential application in drug delivery and targeted cancer therapy.

Harvesting Lost Photons: Plasmon and Upconversion Enhanced Broadband Photocatalytic Activity in Core@Shell Microspheres Based on Lanthanide‐Doped NaYF4, TiO2, and Au

“…To be more specifi c, the following steps were taken sequentially or partially in parallel: 1) Au NPs with the average diameter of ≈5 nm ( Figure S1, Supporting Information) were fabricated by laser ablation on a bulk Au target in water following our previous work; [ 26 ] 2) monodisperse NYF microspheres were prepared according to the previously reported method with some modifi cations. [ 34 ] The average diameter of the spheres is about 500 nm, and they are composed of tiny nanocrystals and show rough surface ( Figure S2, Supporting Information); 3) porous TiO 2 was then deposited onto the NYF core to form core@shell microspheres by adapting the method for synthesizing pure TiO 2 spheres. [ 35 ] The uniform coating of porous TiO 2 around the whole surface of NYF microspheres is clearly evidenced ( Figure S3A, Supporting Information).…”

A novel approach for the preparation of nanosized Gd2O3 structure: The influence of surface force on the morphology of ball milled particles

“…The most important applications of nanosized gadolinium oxide are in medical areas. Because of its safe properties in clinical uses, gadolinium oxides can be used as a gamma absorber and a source in cancer radiation therapy, magnetic resonance imaging contrast agents, magnetic targeting drug carrying, and recently proposed as radiation shielding material for X-ray diagnosis [10][11][12][13][14][15][16][17][18].…”

Template-free synthesis and luminescent properties of hollow Ln:YOF (Ln = Eu or Er + Yb) microspheres

“…In the last years, many research efforts have been focussed on the development of well dispersed hollow spherical particles of different luminescent lanthanide (Ln) based compounds [1][2][3][4][5][6][7][8][9][10][11][12] due to their multifunctional character, which make them suitable for a large variety of applications. Thus, Ln-based luminescent compounds, usually consisting of a host matrix doped with Ln cations, find important applications in lighting [13], display devices [14], solid state lasers [15] and biotechnology (labelling, imaging, drug delivery) [16,17], to mention a few.…”

“…Hitherto, most reports dealing with luminescent Ln-based systems consisting of hollow spheres, involve the use oxidic (oxides [4,6,7,10], phosphates [1.3], vanadates) [9,11,12] or fluoride [2,5,8] hosts. The former have the advantages of their high chemical and thermal stability, whereas fluorides are more preferred than oxides from the optical point of view, since the former have lower vibrational energies and consequently, the quenching of the exited state of the Ln cations through multiphonon relaxation is minimised, resulting in a higher quantum efficiency of luminescence [17,19].…”