BaMoO4:Tb3+ phosphor properties: Synthesis, characterization and photophysical studies

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Europium(III) Concentration Effect on the Spectroscopic and Photoluminescent Properties of BaMoO4:Eu

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sol-gel synthesis of mesoporous CaCu3Ti4O12 thin films and their gas sensing response

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

In2O3 microcrystals obtained from rapid calcination in domestic microwave oven

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The valuable role of renucleation rate in ultrananocrystalline diamond growth

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of Ga incorporation on photoinduced phenomena in Ge-S based glasses

To study the influence of Ga addition on photoinduced effect, GaGeS glasses with constant atomic ratio S/Ge = 2.6 have been prepared. Using Raman spectroscopy, we have reported the effect of Ga on the structural behavior of these glasses. An increase of the glass transition temperature T(g), the linear refractive index and the density have been observed with increasing gallium content. The photoinduced phenomena have been examined through the influence of time exposure and power density, when exposed to above light bandgap (3.53 eV). The correlation between photoinduced phenomena and Ga content in such glasses are shown hereby. (C) 2009 Elsevier B.V. All rights reserved.

Investigation on the structural properties in Er-doped PbTiO3 compounds: A correlation between experimental and theoretical results

The aim of this work is to investigate the structural properties of the (Pb1-xErx)TiO3 (PET) powders, with x varying from 0.01 to 0.08, prepared by the polymeric precursor method. Combined X-ray diffraction, Raman spectroscopy and ab initio calculation reveal a diffuse phase-transition of a tetragonal to a cubic phase. The crystalline models built allowed to calculate electronic properties and to analyze the behavior of the doping element in the structure of the material, which are consistent with the experimental results that indicate the beginning of phase-transition from tetragonal to cubic. (C) 2007 Elsevier B.V. All rights reserved.

Study of Structure and Properties of Bi4Ti3O12 Prepared by Mechanochemical Syntheses

Bi4Ti3O12 powder was synthesized from bismuth oxide and titanium oxide. Mixture of oxides was milled in zirconium oxide jar in the planetary ball-mill during 1, 3 and 6 h. Extended time of milling directed to formation of higher amount of titanates perovskite phase. Bi4Ti3O12 was formed between 1 and 3 h of milling time. The phase formation of Bi4Ti3O12, crystal structure and powder particle size were followed by XRD, Raman spectroscopy and SEM analysis. After milling for various times the powders were compacted by pressing and isothermal sintering. Sample milled for 3 h and subsequently sintered at 1000C for 24 h exhibit a hysteresis loop, confirming that the synthesized material possesses ferroelectric properties. All results affect that the structure Bi4Ti3O12 is strongly dependent on the milling time.

Ligand Exchange Inducing Efficient Incorporation of CisPt Derivatives into Ureasil-PPO Hybrid and Their Interactions with the Multifunctional Hybrid Network

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Photoluminescence in the CaXSr1-xWO4 system at room temperature

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

BaMoO(4) powders processed in domestic microwave-hydrothermal: Synthesis, characterization and photoluminescence at room temperature

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Strain behavior of lanthanum modified BiFeO3 thin films prepared via soft chemical method

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diverse Amorphous Carbonaceous Thin Films Obtained by Plasma Enhanced Chemical Vapor Deposition and Plasma Immersion Ion Implantation and Deposition

Diverse amorphous hydrogenated carbon and similar films containing additional elements were produced by Plasma Enhanced Chemical Vapor Deposition (PECVD) and by Plasma Immersion Ion Implantation and Deposition (PIIID). Thus a-C:H, a-C:H:F, a-C:H:N, a-C:H:Cl and a-C:H:O:Si were obtained, starting from the same feed gases, using both techniques. The same deposition system supplied with radiofrequency (RF) power was used to produce all the films. A cylindrical stainless steel chamber equipped with circular electrodes mounted horizontally was employed. RF power was fed to the upper electrode; substrates were placed on the lower electrode. For PIIID negative high tension pulses were also applied to the lower electrode. Raman spectroscopy confirmed that all the films are amorphous. Chemical characterization of each pair of films was undertaken using Infrared Reflection Absorption Spectroscopy and X-ray Photoelectron Spectroscopy. The former revealed the presence of specific structures, such as C-H, C-O, O-H. The latter allowed calculation of the ratio of hetero-atoms to carbon atoms in the films, e. g. F:C, N:C, and Si:C. Only relatively small differences in elemental composition were detected between films produced by the two methods. The deposition rate in PIIID is generally reduced in relation to that of PECVD; for a-C:H:Cl films the reduction factor is almost four.

Metal carbonyls with zinciron bond: synthesis and vibrational spectra

The compounds of the type LZnFe(CO)4 (L = dien, trien, tn, s-diMeen, Meen) not yet reported and (NH3)3ZnFe(CO)4, already known, were prepared and studied by IR and Raman spectroscopy. The data obtained suggest that LZnFe(CO)4, for L = (NH3)3, dien and trien are monomers with a bipyramidal trigonal configuration around the iron atom, while for L = tn, s-diMeen and Meen the complexes are probably polymers having a center of symmetry with iron atoms octahedrally co-ordinated. © 1979.

Spectroscopic characterization of SnO2 gels - Code: CP11

Excitation and dynamic emission spectra of Eu3+ ions were simultaneously used with FTIR and Raman spectroscopy to study the structural evolution during SnO2 sol → gel → xerogel conversion. Results make evident an increase of the surroundings symmetry for the Eu3+ ions dissolved in SnO2 matrix and a decrease of the amount of hydroxo groups (Sn-OH) during drying. These phenomena were associated to the pursuit of the condensation reaction after gelation. © 1994 Kluwer Academic Publishers.