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Solar Illumination (solar + illumination)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

Graphite Oxide as a Photocatalyst for Hydrogen Production from Water

ADVANCED FUNCTIONAL MATERIALS, Issue 14 2010
Te-Fu Yeh
Abstract A graphite oxide (GO) semiconductor photocatalyst with an apparent bandgap of 2.4,4.3,eV is synthesized by a modified Hummers' procedure. The as-synthesized GO photocatalyst has an interlayer spacing of 0.42,nm because of its moderate oxidation level. Under irradiation with UV or visible light, this GO photocatalyst steadily catalyzes H2 generation from a 20,vol % aqueous methanol solution and pure water. As the GO sheets extensively disperse in water, a cocatalyst is not required for H2 generation over the GO photocatalyst. During photocatalytic reaction, the GO loses some oxygen functional groups, leading to bandgap reduction and increased conductivity. This structural variation does not affect the stable H2 generation over the GO. The encouraging results presented in this study demonstrate the potential of graphitic materials as a medium for water splitting under solar illumination. [source]

Perfluorinated Subphthalocyanine as a New Acceptor Material in a Small-Molecule Bilayer Organic Solar Cell

ADVANCED FUNCTIONAL MATERIALS, Issue 21 2009
Hans Gommans
Abstract The complex refractive index of fluorinated subphthalocyanines (SubPcs) deposited by vacuum sublimation is determined by spectral ellipsometry. Their performance as acceptor material is characterized in a range of donor/acceptor heterojunctions in organic photovoltaic cells (OPVCs) by current,voltage measurements under 1,sun AM 1.5D simulated solar illumination and spectral response. Both electron and hole transfer between donor and acceptor materials is demonstrated. Power conversion efficiencies of 0.96% are found with an open-circuit bias of 940,mV. Hence, it is shown that fluorinated SubPcs can be considered as an acceptor material in OPVCs with an absorption in the visible comparable to that of well-known metallophthalocyanines. [source]

Design of Multilayered Nanostructures and Donor,Acceptor Interfaces in Solution-Processed Thin-Film Organic Solar Cells,

ADVANCED FUNCTIONAL MATERIALS, Issue 10 2008
Hiroaki Benten
Abstract Multilayered polymer thin-film solar cells have been fabricated by wet processes such as spin-coating and layer-by-layer deposition. Hole- and electron-transporting layers were prepared by spin-coating with poly(3,4-ethylenedioxythiophene) oxidized with poly(4-styrenesulfonate) (PEDOT:PSS) and fullerene (C60), respectively. The light-harvesting layer of poly-(p -phenylenevinylene) (PPV) was fabricated by layer-by-layer deposition of the PPV precursor cation and poly(sodium 4-styrenesulfonate) (PSS). The layer-by-layer technique enables us to control the layer thickness with nanometer precision and select the interfacial material at the donor,acceptor heterojunction. Optimizing the layered nanostructures, we obtained the best-performance device with a triple-layered structure of PEDOT:PSS|PPV|C60, where the thickness of the PPV layer was 11,nm, comparable to the diffusion length of the PPV singlet exciton. The external quantum efficiency spectrum was maximum (ca. 20%) around the absorption peak of PPV and the internal quantum efficiency was estimated to be as high as ca. 50% from a saturated photocurrent at a reverse bias of ,3,V. The power conversion efficiency of the triple-layer solar cell was 0.26% under AM1.5G simulated solar illumination with 100,mW,cm,2 in air. [source]

Arrays of Parallel Connected Coaxial Multiwall-Carbon- Nanotube,Amorphous-Silicon Solar Cells

ADVANCED MATERIALS, Issue 38-39 2009
Hang Zhou
Arrays of parallel connected coaxial multiwall-carbon-nanotube,amorphous-silicon solar cells are fabricated. In this configuration, orthogonalization of the directions of light absorption and charge-carrier collection is realized. Under simulated solar illumination (AM 1.5,G), the short-circuit current of our carbon-nanotube enhanced solar cell is ,25% higher than that of the planar cell. [source]

One-Dimensional Quantum-Confinement Effect in ,-Fe2O3 Ultrafine Nanorod Arrays,

ADVANCED MATERIALS, Issue 19 2005
L. Vayssieres
A 1D quantum confinement effect in hematite thin films consisting of oriented ultrafine nanorod bundles (see Figure) is investigated by resonant inelastic x-ray scattering of synchrotron radiation. The direct observation of a substantial bandgap increase compared to bulk hematite is revealed. This finding shows that these low-dimensional nanomaterials may be used for the generation of hydrogen by solar illumination without applied bias. [source]