Thin Films In Aqueous Solution Research Articles

Nano/Micro Patterning of Inorganic Thin Films

Abstract The present review is focused on the site-selective deposition of inorganic thin films on self-assembled monolayer (SAM) templates. SAMs were used to modify the substrate surface with chemical functional groups. The patterned SAM substrate was prepared by exposing the SAM substrate to UV light through photomasks for photocleavage. The patterned SAM was used as the templates for deposition of ceramic thin films in aqueous solutions. The preparation and characterization methods of SAMs, and the preparation of the patterned SAM templates are explained. Solution chemistry for the deposition of ceramic oxides and the physics and chemistry of interfaces are described. Experimental examples are given to explain how these aspects influence the formation of films and their properties. Various examples of site-selective deposition of ceramic oxides on SAM templates are explained with classification into three categories: patterning by site-selective attachment of homogeneously nucleated particles, patterning by surface-selective heterogeneous nucleation and growth, and patterning by catalyst-induced heterogeneous nucleation. We also describe pattern-deposition on flexible substrates and future views to improve the pattern resolution.

Monitoring Organic Thin Film Growth In Aqueous Solution In-situ With A Combined Quartz Crystal Microbalance and Ellipsometry

AbstractThe change of the visible light ellipsometric parameters and mechanical harmonic frequencies of a hydrophobic gold surface attached to a quartz crystal are measured in aqueous solution during deposition of synperonic polymer thin film. The ellipsometry data reveal the amount of polymer mass attached to the surface, while the mechanical resonance shifts are caused by the total mass attached to the surface. Analysis of the combined ellipsometry and quartz crystal microbalance data reveal that the polymer thin film has a high water content, and we determine in-situ, for the first time, the porosity, or the water content, of a polymer thin film in aqueous solution.

The effect of annealing on photocatalytic properties of nanostructured titanium dioxide thin films

The photocatalytic degradation of a non-biodegradable azo dye called (C.I. Direct 80, Red Sulphonyl 3BL) was investigated using TiO 2 thin films in aqueous solution under irradiation of a mercury lamp Philips (UV-C) light source. The effect of operational parameters, i.e., annealing temperature of thin film, substrate nature on which TiO 2 films were deposited, film thickness, pH of the solution, dye concentration, and irradiation time on the degradation rate of azo dye aqueous solutions was examined. Results show that the employment of efficient photocatalyst and the selection of optimal operational parameters lead to complete decolorization. The best conditions for maximum photocatalytic degradation were found to be pH 1 at 5 ppm concentration of dye over TiO 2 thin films deposited on glass substrate coated with indium-tin oxide having 350 nm thicknesses annealed at 550 °C. The samples are all in the complete anatase phase and the particle size is in nanometer scale which is confirmed by XRD pattern analysis.

Control of Nucleation in Solution Growth of Anatase TiO2 on Glass Substrate

Low-temperature preparation of ceramic thin films in aqueous solution is an important new field in the synthesis of functional materials. This work examines control of nucleation in the growth of anatase titania (TiO2) on a common glass substrate at 55−80 °C using an inorganic precursor, TiF4. It is found that TiO2 on fused silica is first formed as single-crystalline nuclei during an initial heterogeneous nucleation. These TiO2 crystallites elongate along the [001] direction with their [110] axis perpendicular to the glass substrate; the elongated nuclei later grew into a round flowerlike morphology owing to a significant increase in homogeneous nucleation rate during the continued growth. The flowerlike polycrystalline TiO2 islands, either as discrete crystallites or as lined crystallite arrays, subsequently develop into a planar crystallite monolayer. In general, low-pH condition suppresses heterogeneous nucleation and growth; this allows a self-alignment of thin threadlike crystallites. In contrast, h...

Corrosion behavior of boron-carbon-nitride films grown by magnetron sputtering

The corrosion behavior of BCN thin films in aqueous solution was investigated. BCN films with different composition were deposited on a platinum plate by magnetron sputtering in the thickness range of 150–280 nm. In order to understand effect of pH of solutions, BC 2.4N samples were immersed in 1 M HCl, 1 M NaCl and 1 M NaOH solution at 298 K, respectively. BCN samples with different carbon content were immersed in 1 M NaOH solutions to investigate the effect of chemical composition on corrosion resistance. The corrosion rate of the samples were measured by ellipsometry. The corrosion rates of B 1.0C 2.4N 1.0 films in the immersion test were NaOH>NaCl>HCl in sequence. With increasing carbon content in BCN films, the corrosion resistance of BCN films is enhanced. The lowest corrosion rate was obtained for B 1.0C (3.2–4.4)N 1.2 films.

Sol-Gel Glasses as New Waveguides for Optical Immunosensors

ABSTRACTIn order to develop an optical immunosensor based on Surface Plasmon Resonance (SPR) and guided waves propagation, the sol-gel process has been used to prepare thin films of amorphous silica, deposited by spin coating on a gold-coated glass slide, and possessing chemically active functional groups (SH, NH2...). After activation of the sol-gel film in aqueous buffers by a bifunctional coupling agent, biological molecules such as antibodies could be covalently bonded on or inside the sol-gel film. Therefore, the behaviour of the functionalized silica thin films in aqueous solutions has been analyzed by SPR and guided waves propagation. The matrix hydrophilicity has been studied with different mixtures of functionalized silicon precursors forming organic-inorganic hybrid films. Immunoassays outline the possibility of obtaining covalent binding of antibodies to the sol-gel matrix with optimal stability and biological activity.

A photoelectrochemical cell based on chemically deposited Sb 2Se 3 thin film electrode and dependence of deposition on various parameters

The photoelectrochemical behavior of chemically deposited Sb 2Se 3 thin film in aqueous solution is studied. the short-circuit photocurrent is about 0.45 mA/cm 2 and open-circuit photovoltage is about 0.37 V. This paper also describes the dependence of the deposition on pH, temperature and deposition mixture.

Semiconductor Liquid Junction Solar Cell Based on Chemically Deposited Bi2 S 3 Thin Film and Some Semiconducting Properties of Bismuth Chalcogenides

The photoelectrochemical behavior of chemically deposited thin film in aqueous solution is studied. This paper also describes the dependence of the deposition of bismuth chalcogenides on the pH of the solution. The electrical resistance, mobility, and carrier concentration of bismuth chalcogenides have been measured. Optical absorption spectra reveal the bandedges which are 1.47 and 0.35 eV for and , respectively. The activation energy of electrical conduction of obtained is ∼0.9 eV.