Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

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Dye-Sensitized Solar Cells

Lanthanide-based luminescent hybrid materials.

Here, we present a review of the antibacterial effects of silver nanomaterials, including proposed antibacterial mechanisms and possible toxicity to higher organisms. For purpose of this review, silver nanomaterials include silver nanoparticles, stabilized silver salts, silver–dendrimer, polymer and metal oxide composites, and silver-impregnated zeolite and activated carbon materials. While there is some evidence that silver nanoparticles can directly damage bacteria cell membranes, silver nanomaterials appear to exert bacteriocidal activity predominantly through release of silver ions followed (individually or in combination) by increased membrane permeability, loss of the proton motive force, inducing de-energization of the cells and efflux of phosphate, leakage of cellular content, and disruption DNA replication. Eukaryotic cells could be similarly impacted by most of these mechanisms and, indeed, a small but growing body of literature supports this concern. Most antimicrobial studies are performed in simple aquatic media or cell culture media without proper characterization of silver nanomaterial stability (aggregation, dissolution, and re-precipitation). Silver nanoparticle stability is governed by particle size, shape, and capping agents as well as solution pH, ionic strength, specific ions and ligands, and organic macromolecules—all of which influence silver nanoparticle stability and bioavailability. Although none of the studies reviewed definitively proved any immediate impacts to human health or the environment by a silver nanomaterial containing product, the entirety of the science reviewed suggests some caution and further research are warranted given the already widespread and rapidly growing use of silver nanomaterials.

https://link.springer.com/content/pdf/10.1007%2Fs11051-010-9900-y.pdf

A review of the antibacterial effects of silver nanomaterials and potential implications for human health and the environment

Transparent conductors as solar energy materials: A panoramic review

Electrochromic tungsten oxide films: Review of progress 1993–1998

Characterization of spinel Co3O4 and Li-doped Co3O4 thin film electrocatalysts prepared by the sol–gel route

Osteryoung, J. Electrochem. Soc. 1997, 144, 3881. c) A. B. McEwen, H. L.Ngo, K. LeCompte, J. L. Goldman, J. Electrochem. Soc. 1999, 146, 1687.[6] a) C. J. Bowlas, D. W. Bruce, K. R. Seddon, Chem. Commun. 1996, 1625.b) K. M. Lee, C. K. Lee, I. J. B. Lin, Chem. Commun. 1997, 899. c) J. D.Holbrey, K. R. Seddon, J. Chem. Soc., Dalton Trans. 1999, 2133. d) F.Neve, O. Francescangeli, A. Crispini, J. Charmant, Chem. Mater. 2001, 13,2032.[7] a) J. S. Wilkes, M. J. Zaworotko, J. Chem. Soc., Chem. Commun. 1992,965. b) R. Hagiwara, Y. Ito, J. Fluorine Chem. 2000, 105, 221.[8] a) B. Neumann, C. Sauer, S. Diele, C. Tschierske, J. Mater. Chem. 1996, 6,1087. b) M. Kolbel, T. Beyersdorff, C. Tschierske, S. Diele, J. Kain, Chem.Eur. J. 2000, 6, 3821. c) T. Kato, Struct. Bonding 2000, 96, 95.[9] M. Hird, G. W. Gray, K. J. Toyne, Mol. Cryst. Liq. Cryst. 1991, 206, 187.[10] D. L. Hughes, Org. React. 1992, 42, 335.

A High-Performance Solid-State Dye-Sensitized Photoelectrochemical Cell Employing a Nanocomposite Gel Electrolyte Made by the Sol–Gel Route

Thin films of the cubic spinel Co{sub 3}O{sub 4} were prepared by the sol-gel route from a Co(II) sulfate precursor using a dip-coating technique. The films (50 to 60 nm thick) were deposited on indium-tin oxide glass substrates with a single dipping. The electrochromic properties of the films were studied in an aqueous alkaline electrolyte (0.1 M LiOH) using cyclic voltammetry (CV) and in situ UV-vis spectroelectrochemistry. The intermediate oxide products that appeared during cycling at current peak potentials were analyzed by x-ray diffraction (XRD) and ex situ Fourier transform infrared (FTIR) reflection-absorption spectroscopy performed at near-grazing incidence angle conditions (NGIA). High hydration of the spinel structure enables complex redox processes to take place inside the structure or on the surface of the film when potential cycling is performed. Vibrational bands characteristic of the formation of CoO, Co(OH){sub 2}, and hydrated Co{sub 3}O{sub 4} phases have been assigned and discussed according to the results obtained from ex situ NGIA FTIR, CV, and XRD studies. The change in transmittance ({lambda} = 634 nm) between bleached and colored states for single-dipped films was 25%, and for electrochromic efficiency ({eta}) was approximately 25 cm{sup 2}/C.

Structural and Spectroelectrochemical Investigations of Sol-Gel Derived Electrochromic Spinel Co[sub 3]O[sub 4] Films

The activity and selectivity of the Ce1−xCuxO2−δ catalysts prepared by co-precipitation and by sol–gel methods were studied in the catalytic wet oxidation (CWO) of phenol at 432 K and at 7.3 bar oxygen partial pressure in a semibatch CST reactor. Both types of catalysts are very stable under hydrothermal reaction conditions at low pH values. It has been found that activity and selectivity increase with the dispersion of copper oxide phase on the cerium oxide. While the Cu content was equal in both types of catalysts, the samples prepared by sol–gel technique are up to four times more active and about 25% more selective toward CO2 formation than the samples prepared by co-precipitation at given reaction conditions. The heterogeneously initiated radical mechanism results in autocatalytic type kinetics. The activity and selectivity depend on the initial concentration of heterogeneously catalytically formed radicals in each subsequent oxidation step. Between these steps the radicals react further on in liquid phase.

CWO of phenol on two differently prepared CuO–CeO2 catalysts

In a continuation of previous studies, the wetting properties of the hydrophobic diureapropyltriethoxysilane [bis(aminopropyl)-terminated polydimethylsiloxane (1000)] (PDMSU) sol-gel hybrid, which forms washing-resistant water-repellent finishes on cotton fabrics, were further investigated. The addition of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) to PDMSU resulted in a highly apolar low-energy surface on aluminum with gammaStotal equal to 14.5 mJ/m2 and a DetlaGiwi value of -82 mJ/m2. Mixed PFOTES-PDMSU finishes applied on cotton fabrics increased the water contact angles (thetaw) from approximately 130 degrees (PDMSU) to 147 degrees, also imparting oleophobicity (thetadiiodomethane=130 degrees, thetan-hexadecane=120 degrees) to the finished cotton fabrics. Washing caused breakage of the coating's integrity as established from SEM, which was attributed to the partial removal of PFOTES from the composite films, also shown by subtractive IR attenuated total reflectance (ATR) and XPS spectral measurements made on washed and unwashed fabrics. The antibacterial properties of the PFOTES-PDMSU-finished fabrics were assessed with the transfer method (EN ISO 20743:2007), revealing that the reduction of Escherichia coli bacteria on unwashed cotton fabrics was nearly 100%. Moreover, for washed (10 times) cotton fabrics a much higher bacterial reduction was noted for the PFOTES-PDMSU finishes (60.6+/-10.8%), surpassing PDMSU (30.4+/-6.1%) and commercial fluoroalkoxysilane (FAS) (21.9+/-5.7%) finishes. The structure of PFOTES-PDMSU gels, xerogels, and the corresponding coatings was investigated by analyzing the 29Si NMR and IR ATR spectra and comparing them with the spectra of PFOTES and octameric (T8) PFOTES based polyhedra. The results revealed the tendency of PFOTES to condense in octameric silsesquioxane polyhedra (T8), coexisting in the PDMSU sol-gel network with cyclic tetramers (T4(OH)4) and open cube-like species (T7(OH)3). The presence of -OH-functionalized PFOTES silsesquioxanes, established even in coatings heat-treated at 140 degrees C (15 min), also explained the excellent washing fastness of PFOTES finishes on cotton fabrics. The regenerative nature of the water- and oil-repellent properties of washed PFOTES-PDMSU-finished cotton fabrics was attributed to the surface mobility of the T8 PFOTES based polyhedra, ousted from the coating interior during consecutive washings.

Boris Orel

Papers

Characterization of spinel Co3O4 and Li-doped Co3O4 thin film electrocatalysts prepared by the sol–gel route

A High-Performance Solid-State Dye-Sensitized Photoelectrochemical Cell Employing a Nanocomposite Gel Electrolyte Made by the Sol–Gel Route

Structural and Spectroelectrochemical Investigations of Sol-Gel Derived Electrochromic Spinel Co[sub 3]O[sub 4] Films

CWO of phenol on two differently prepared CuO–CeO2 catalysts

Structural Properties and Antibacterial Effects of Hydrophobic and Oleophobic Sol-Gel Coatings for Cotton Fabrics