Deposition and characterization of BiVO4 thin films and evaluation as photoanodes for methylene blue degradation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Growth of Al2O3 thin film by oxidation of resistively evaporated Al on top of SnO2, and electrical properties of the heterojunction SnO2/Al2O3

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of pH of colloidal suspension on crystallization and activation energy of deep levels in SnO2 thin films obtained via sol-gel

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Deposição de filmes de ZrO2 modificados sobre substratos metálicos

This work makes use of the Pechini process for synthesis of the solutions and the dip-coating process for the addition of zirconium oxide films pure and doped cerium metal substrates. The metals with ceramic substrates were subjected to severe conditions of salinity. The x-ray fluorescence of the substrate showed a great diversity of chemical elements. The x-ray diffraction of the samples showed the phase of iron substrate because the thickness of nano-thin film. Tests using an LPR probe showed that the film presents with zirconia corrosion independent of film thickness. The substrates of ZrO2-doped ceria showed low chemical attack of the salt in films with less than 15 dives. The results imply that ultrathin films are shown in protecting metallic substrates

Effects of annealing on the crystallization and roughness of PLZT thin films

Lead lanthanum zirconate titanate (PLZT) thin films with stoichiometry (9/65/35) were prepared by a dip-coating process using a polymeric organic solution. The solution viscosity was adjusted in the range of 15-56 cP. Silicon (100) substrates were previously cleaned and then immersed in the solution. The withdrawal speed of substrate from the solution was adjusted within a range of 5 to 20 mm/min. The coated substrates were thermally treated in the 450-700 degreesC temperature range. Surface roughness and crystallization of these films are strongly dependent on the annealing conditions. Infrared and X-ray diffraction data for PLZT powders heat-treated at 650 degreesC for 3 h show that the material is free of carbonate phases and crystalline. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Effect of precursor solution on the formation of perovskite phase of Pb(Mg-1/Nb-3(2/3))O-3 thin films

Precursor solutions for Pb(Mg1/3Nb2/3)O-3 (PMN) synthesis were obtained by Pechini's method. The influence of the concentration of organic materials on the phase formation has been studied. For this purpose, PMN solutions were prepared with different precursors and were characterized by thermogravimetric and differential thermal analysis. The obtained solutions were deposited onto a Si (100) substrate by dip coating and pre-treated in a hot plate at 300 degreesC for 1 h. The films were annealed at 600, 700, 800 and 900 degreesC for 1 h and characterized by X-ray diffraction. The perovskite phase was formed after annealing at 600 and 700 degreesC when the solution of PMN was prepared with a lower amount of organic material and starting with mobium oxide. By increasing the temperature to 800 or 900 degreesC, only the formation of pyrochlore phase was observed. With the solution prepared from mobium ethoxide, only the presence of pyrochlore phase was observed independently of the annealing temperature. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Influence of oxygen flow on crystallization and morphology of PLZT thin films

PLZT thin films were prepared by a dip coating process using Pechini's method, also known as polymeric precursor method. The PLZT solution was obtained from a mixture of the individual cation solutions and the process to prepare each solution is based on metallic citrate polymerization. The viscosity of the PLZT solution was adjusted at 40 cP while the ionic concentration was adjusted at 0.1 M. PLZT solutions were deposited on silicon (100) and platinum coated silicon (100) substrates with withdrawal speed at 5 mm/min. The coated substrates were thermally treated with a heating rate of 1 degreesC/min up to 300 degreesC and 5 degreesC/min up to 650 degreesC in order to obtain homogeneous and cracks free films. The influence of oxygen flow on crystallization and morphology of PLZT (9/65/35) thin film is discussed. (C) 2002 Elsevier B.V. Ltd and Techna S.r.l. All rights reserved.

Influence of viscosity and ionic concentration on morphology of PLZT thin films

PLZT thin films were prepared by a dip-coating process using Pechini's method. The PLZT solution was obtained from the mixture of the cation solutions. The viscosity of the solution was adjusted in the range of 20-40 cP, while the ionic concentration was adjusted in the range of 0.1 and 0.2 M. PLZT solutions were deposited on Si (1 0 0) substrate with withdrawal speed at 5 mm/min. The coated substrates were thermally treated with heating rate of 1 degreesC/min up to 300 and 5 degreesC/ min up to 650 degreesC in order to obtain homogeneous and crack free films. The influence of viscosity and ionic concentration on crystallization and morphology of PLZT (9/65/35) thin film will be discussed. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Highly corrosion resistant siloxane-polymethyl methacrylate hybrid coatings

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Color tunability of intense upconversion emission from Er3+-Yb3+ co-doped SiO2-Ta2O5 glass ceramic planar waveguides

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

Erbium-activated silica-zirconia planar waveguides prepared by sol-gel route

Er(3+) doped (100-x)SiO(2)-xZrO(2) planar waveguides were prepared by the sol-gel route, with x ranging from 10 up to 30 mol%. Multilayer films doped with 0.3 mol% Er(3+) ions were deposited on fused quartz substrates by the dip-coating technique. The thickness and refractive index were measured by m-line spectroscopy at different wavelengths. The fabrication protocol was optimized in order to confine one propagating mode at 1.5 mu m. Photoluminescence in the near and visible region indicated a crystalline local environment for the Er(3+) ion. (c) 2007 Elsevier B.V. All rights reserved.

Filmes delgados luminescentes obtidos a partir de hidroxicarbonatos de ítrio ativados por európio ou térbio

These films were obtained by dip coating. Parameters like dislocation velocity; number of deposits, suspension concentration, and number of deposits followed or not by heat treatment between each deposit and calcination temperature were evaluated for establishing the best homogeneity. The obtained films were characterized in terms of their morphology, optical quality and photoluminescence by scanning electron microscopy (SEM), UV-vis absorption spectrophotometry and luminescence spectroscopy, respectively. The morphologic and luminescent characteristics showed dip coating as good laboratory technique for development of thin films for optical applications.

Visible emission from Er-doped SnO2 thin films deposited by sol-gel

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

Determinação de diagramas de bandas de energia e da borda de absorção em SnO2, depositado via sol-gel, sobre quartzo

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

Resistividade do filme depositado via sol-gel e estado de oxidação do dopante Ce na matriz SnO2

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