Electrophoretic deposition of TiO2/Er3+ nanoparticulate sols.

TiO(2) and TiO(2)/Er(3+) nanoparticulate sols were obtained by the colloidal sol-gel route. Thanks to the combination of three optical techniques (laser diffraction, LD, dynamic light scattering, DLS, and multiple light scattering, MLS), the peptization time was quantified, demonstrating that erbium(III) ions retard the process. The isoelectric point of TiO(2) shifts up to higher pH's when Er(3+) ions are present, which suggests that they are adsorbed onto the surface of the TiO(2) nanoparticles. Moreover, the viscosity of the sols increases when the erbium(III) amount increases. The xerogels obtained from each sol were characterized by XRD and HRTEM, obtaining in all cases anatase as the major phase, although traces of brookite were also present. In the EPD experiments, the addition of ethanol was necessary to reduce the water hydrolysis and facilitate the drying process. As a result, transparent thin films were obtained at short times and low current densities and opal films for larger current densities and deposition times; in addition, the thickness, measured by ellipsometry, increased gradually, but the refractive index did not change significantly (1.9-2). The topography profile of the films and the particle size were obtained by atomic force microscopy (AFM), giving similar values to those measured by DLS, indicating that the addition of ethanol helps to maintain stabilization without further agglomeration or sedimentation.

[1]  Diana Golodnitsky,et al.  Electrophoretic deposition of lithium iron phosphate cathode for thin-film 3D-microbatteries , 2012 .

[2]  K. Ho,et al.  Fabrication and characterization of plastic-based flexible dye-sensitized solar cells consisting of crystalline mesoporous titania nanoparticles as photoanodes , 2011 .

[3]  A. Boccaccini,et al.  Titania and titania–silver nanocomposite coatings grown by electrophoretic deposition from aqueous suspensions , 2010 .

[4]  T. Uchikoshi,et al.  Application of electrophoretic deposition for inner surface coating of porous ceramic tubes , 2010 .

[5]  Y. Sakka,et al.  Application of constant current pulse to suppress bubble incorporation and control deposit morphology during aqueous electrophoretic deposition (EPD) , 2009 .

[6]  Y. Sakka,et al.  Preparation of Crystalline‐Oriented Titania Photoelectrodes on ITO Glasses from a 2‐Propanol–2,4‐Pentanedione Solvent by Electrophoretic Deposition in a Strong Magnetic Field , 2009 .

[7]  A. Fujishima,et al.  TiO2 photocatalysis and related surface phenomena , 2008 .

[8]  M. T. Colomer,et al.  Determination of Peptization Time of Particulate Sols Using Optical Techniques : Titania As a Case Study , 2008 .

[9]  Xiaobo Chen,et al.  Titanium dioxide nanomaterials: synthesis, properties, modifications, and applications. , 2007, Chemical reviews.

[10]  J. Gómez‐Herrero,et al.  WSXM: a software for scanning probe microscopy and a tool for nanotechnology. , 2007, The Review of scientific instruments.

[11]  D. Bavykin,et al.  Reversible storage of molecular hydrogen by sorption into multilayered TiO2 nanotubes. , 2005, The journal of physical chemistry. B.

[12]  C. Mignotte Structural characterization for Er3+-doped oxide materials potentially useful as optical devices , 2004 .

[13]  Seokwoo Jeon,et al.  Hydrothermal Synthesis of Er-Doped Luminescent TiO2 Nanoparticles , 2003 .

[14]  Xinwei Zhao,et al.  Change in photoluminescence from Er-doped TiO2 thin films induced by optically assisted reduction , 2002 .

[15]  Craig M. Herzinger,et al.  Ellipsometric determination of optical constants for silicon and thermally grown silicon dioxide via a multi-sample, multi-wavelength, multi-angle investigation , 1998 .

[16]  J. Mugnier,et al.  Up-conversion fluorescence spectroscopy in Er3+: TiO2 planar waveguides prepared by a sol-gel process , 1996 .

[17]  Estrella Alvarez,et al.  Surface Tension of Alcohol Water + Water from 20 to 50 .degree.C , 1995 .

[18]  A. L. Patterson The Scherrer Formula for X-Ray Particle Size Determination , 1939 .

[19]  M. T. Colomer,et al.  Peptization of Nanoparticulate Titania Sols Prepared Under Different Water-Alkoxide Molar Ratios , 2010 .

[20]  A. Boccaccini,et al.  Electrophoretic deposition: From traditional ceramics to nanotechnology , 2008 .

[21]  M. T. Colomer,et al.  Colloidal stability of nanosized titania aqueous suspensions , 2008 .

[22]  A. Sanchez-Herencia,et al.  YSZ/Ni–YSZ semi-cells shaped by electrophoretic deposition , 2007 .

[23]  C. Pagnoux,et al.  Fabrication of titania dense layers by electrophoretic deposition in aqueous media , 2006 .

[24]  R. Moreno,et al.  Advanced ceramics via EPD of aqueous slurries , 2000 .