LaAlO3 hollow spheres: synthesis and luminescence properties

Nearly monodisperse LaAlO(3) hollow spheres are synthesized by a novel precursor thermal decomposition method. Spherical colloids of capsulelike precursors with uniform diameters of 273 ± 35 nm have been synthesized by a solvothermal method. These spherical colloids could convert to LaAlO(3) hollow spheres with diameters of 166 ± 26 nm by a thermal decomposition process. The thermal transformation process from the precursors to LaAlO(3) was characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), and the Fourier transform infrared spectroscopy (FT-IR). By the doping of various lanthanide ions (Sm(3+), Eu(3+), and Tb(3+)), the emission luminescence of lanthanide-doped LaAlO(3) hollow microspheres can be tuned from red to green. In particular, these luminescent LaAlO(3) hollow spheres can be well dispersed in polar solvents such as the ethanol and water, which broadens the range of potential applications of these hollow spheres. The UV-vis absorption spectra show energy absorption at 211, 223, and 313 nm corresponding to the host lattice absorption and charge-transfer transitions. The results are in good agreement with the peaks observed in the excitation spectra.