Controlled fabrication of rare earth fluoride superstructures via a simple template-free route

A new and simple route to fabricate rare earth metal fluoride superstructures has been investigated. Typically, doughnut- and shuttle-shaped EuF3 superstructures were controllably synthesized by using sodium tetrafluoroborate (NaBF4) as a fluorine source to react with metal nitrate in aqueous solution under ambient conditions. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated that different superstructures can be obtained by changing the concentration of the reactants. The photoluminescence (PL) spectra of the as-synthesized EuF3 measured with an excitation source wavelength of 380 nm showed that the emission intensity at different wavelengths can be adjusted by changing the morphology of EuF3. Moreover, our experiments indicated that the fabrication of the rare earth metal fluoride superstructures could be readily scaled up to grams