			Home About us Contact

Deposition Approach (deposition + approach)

Distribution by Scientific Domains

Polymers and Materials Science	80%

Selected Abstracts

Enhanced Photocatalytic Activity using Layer-by-Layer Electrospun Constructs for Water Remediation

ADVANCED FUNCTIONAL MATERIALS, Issue 15 2010
Jung Ah Lee
Abstract Endocrine disruptors such as bisphenol A (BPA) are environmental pollutants that interfere with the body's endocrine system because of their structural similarity to natural and synthetic hormones. Due to their strong oxidizing potential to decompose such organic pollutants, colloidal metal oxide photocatalysts have attracted increasing attention for water detoxification. However, achieving both long-term physical stability and high efficiency simultaneously with such photocatalytic systems poses many challenges. Here a layer-by-layer (LbL) deposition approach is reported for immobilizing TiO2 nanoparticles (NPs) on a porous support while maintaining a high catalytic efficiency for photochemical decomposition of BPA. Anatase TiO2 NPs ,7,nm in diameter self-assemble in consecutive layers with positively charged polyhedral oligomeric silsesquioxanes on a high surface area, porous electrospun polymer fiber mesh. The TiO2 LbL nanofibers decompose approximately 2.2,mg BPA per mg of TiO2 in 40,h of illumination (AM 1.5G illumination), maintaining first-order kinetics with a rate constant (k) of 0.15,h,1 for over 40,h. Although the colloidal TiO2 NPs initially show significantly higher photocatalytic activity (k,,,0.84,h,1), the rate constant drops to k,,,0.07,h,1 after 4,h of operation, seemingly due to particle agglomeration. In the BPA solution treated with the multilayered TiO2 nanofibers for 40,h, the estrogenic activity, based on human breast cancer cell proliferation, is significantly lower than that in the BPA solution treated with colloidal TiO2 NPs under the same conditions. This study demonstrates that water-based, electrostatic LbL deposition effectively immobilizes and stabilizes TiO2 NPs on electrospun polymer nanofibers for efficient extended photochemical water remediation. [source]

High-Efficiency Solar Cell with Earth-Abundant Liquid-Processed Absorber

ADVANCED MATERIALS, Issue 20 2010
Teodor K. Todorov
A composite liquid deposition approach merging the concepts of solution and particle-based coating for multinary chalcogenide materials is demonstrated. Photovoltaic absorbers based on earth-abundant Cu,Zn,Sn,S,Se kesterites show exceptional phase purity and are incorporated into solar cells with power conversion efficiency above 9.6%, bringing the state of the art of kesterite photovoltaic materials to a level suitable for possible commercialization. [source]

Epitaxial Solution Deposition of YBa2Cu3O7,, -Coated Conductors

INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 1 2005
P. G. Clem
A variety of solution deposition routes have been reported for processing complex perovskite-based materials such as ferroelectric oxides and conductive electrode oxides, due to ease of incorporating multiple elements, control of chemical stoichiometry, and feasibility for large area deposition. Here, we report an extension of these methods toward long length, epitaxial film solution deposition routes to enable biaxially oriented YBa2Cu3O7,, (YBCO)-coated conductors for superconducting transmission wires. Recent results are presented detailing an all-solution deposition approach to YBCO-coated conductors with critical current densities Jc (77 K)>1 MA/cm2 on rolling-assisted, biaxially textured, (200)-oriented Ni,W alloy tapes. Solution-deposition methods such as this approach and those of other research groups appear to have promise to compete with vapor phase methods for superconductor electrical properties, with potential advantages for large area deposition and low cost/kA·m of wire. [source]

Hybrid Light-Emitting Diodes from Microcontact-Printing Double-Transfer of Colloidal Semiconductor CdSe/ZnS Quantum Dots onto Organic Layers,

ADVANCED MATERIALS, Issue 10 2008
Aurora Rizzo
A novel dry deposition approach is developed to transfer arrays of colloidal quantum dots onto organic thin films, as illustrated in the figure. A red light-emitting device combining inorganic and organic components is fabricated based on this simple transfer protocol. [source]

Characterization of single-walled carbon nanotubes synthesized using iron and cobalt nanoparticles derived from self-assembled diblock copolymer micelles

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2010
Qiang Fu
Abstract We present a comparative study of single-walled carbon nanotubes grown using iron and cobalt nanoparticles as catalysts via the chemical vapor deposition approach. Monodispersed iron and cobalt oxide nanoparticles with an average size of 2 nm were prepared using a polystyrene- b -poly (4-vinylpyridine) diblock copolymermicelle template. The 2 nm iron oxide nanoparticles generated single-walled carbon nanotubes with an average diameter of 1.5 nm while 2 nm cobalt oxide nanoparticles produced single-walled carbon nanotubes with an average diameter of 1.0 nm. To achieve high growth yield using iron nanoparticles as catalyst, higher carbon feed rate is required. These findings demonstrate the importance of the synergic interaction between catalyst and carbon precursor in single-walled carbon nanotube formation. It also elucidates the important role of catalyst chemical composition on carbon nanotube properties. Copyright © 2010 John Wiley & Sons, Ltd. [source]