Tb Nanoparticles Research Articles

Continuous production of phosphor YAG:Tb nanoparticles by hydrothermal synthesis in supercritical water

Phosphor YAG:Tb ((Y 2.7Tb 0.3)Al 5O 12) nano particles were synthesized by a hydrothermal method at supercritical conditions (400 °C and 30 MPa) using a flow reactor. Hydroxide sol solutions formed by stoichiometric aluminum nitrate, yttrium nitrate, terbium nitrate and potassium hydroxide solutions. The relationship between particle size and experimental variables including pH, concentration of coexistent ions and hydroxide sol were investigated. Particles were characterized by XRD, TEM and photo-luminescence measurements. Particle size of YAG:Tb became finer as pH was increased or potassium nitrate concentration of the starting metal salt solution was increased. By removing the coexisting ions (NO 3 −, K +) from the metal salt solution, single phase YAG:Tb particles with 20 nm particle size were obtained. The emission spectra of YAG:Tb particles of 14 nm shows a blue shift.

Magnetic properties of gadolinium and terbium nanoparticles produced via multilayer precursors

Gd and Tb nanoparticles were obtained via annealing of sputtered multilayer precursors. Detailed structural examination, involving energy-filtered imaging and high-resolution electron microscopy along with transmission electron microscopy and scanning electron microscopy techniques, revealed an island structure for the rare earths within the precursors, which further develops to nanoparticles upon annealing. A dramatic change in the magnetic characteristics of the nanoparticles is observed comparing to the bulk. Magnetic data are discussed to distinguish between true size effects and superparamagnetism. The obtained results give a credit to the former scenario.

Magnetic properties of Tb (0 0 0 1) particles on Nb (1 1 0)

We grow epitaxial Tb (0 0 0 1) nanoparticles on Nb (1 1 0) surfaces under UHV conditions in a Stranski–Krastanov mode. After performing in situ chemical and structural characterization, we protect the particles with a Nb over-layer to perform ex situ SQUID hysteresis loop measurements. The saturation magnetization and the basal coercivity in the Tb particles are modified in comparison to bulk properties.

Carboxylic-containing copolymer as template to prepare CdS, ZnS and doped nanoparticles

CdS, CdS:Mn, ZnS, ZnS:Mn and ZnS:Tb nanoparticles were prepared by using carboxylic-containing copolymer, polystyrene-maleic anhydride (PSM), as template. Average particle size, 2.5 nm for CdS nanoparticles, is deduced from UV-vis absorption spectra and consistent with the observation of TEM. Characteristic emissions of the doping ions can be observed and the energy transfer from the host to the doping ions is verified. Fourier transform infrared (FTIR) spectra were studied to confirm the bonding effect of the copolymer and the metal ions. PSM hydrolyzed and chelated metal ions by its carboxylic group, and then performed as a protection layer after the formation of nanoparticles.

PHOTOLUMINESCENCE OF ZnO:Tb NANOPARTICLES

Terbium-doped zinc oxide nanoparticles have been prepared by hydrolyzing zinc acetate and terbium acetate. Nanoparticle-matrix-facilitated photoluminescence which is related to Tb3+ ions has been observed for ZnO:Tb nanoparticles. The dependence of emission intensity on doping concentration of Tb3+ ions has been investigated. An energy transfer from excited states of ZnO hosts to dopants is disclosed by the fact that the emission intensity of Tb3+ centers increases with increasing Tb content at the expense of emission from defect states in ZnO matrix.

Preparation and Characterization of Garnet Phosphor Nanoparticles Derived from Oxalate Coprecipitation

Terbium-activated Y3Al5O12(YAG:Tb) phosphor nanoparticles with homogeneous grain size and crystallinity have been prepared at 1000°C by heat treatment of a metal oxalate precursor derived from an alkaline coprecipitation route. The diffraction profile of as-prepared YAG:Tb nanoparticles can be indexed as a garnet structure and exhibits peak broadening phenonmenon, as revealed by X-ray diffraction (XRD) data. Grains of YAG:Tb nanoparticles appear to be irregularly spherical or elliptical and their sizes range from 60 to 70 nm, as indicated by morphological studies from bright-field transmission electron microscopy (TEM) imaging. Furthermore, the photoluminescence (PL) spectra of the (Y2.9Tb0.1)Al5O12phase were investigated to determine the energy level of electron transition related to luminescence processes and the possible blue shift in the excitation or emission PL spectra.