1,224 research outputs found
Index to 1985 NASA Tech Briefs, volume 10, numbers 1-4
Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1985 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences
Index to 1986 NASA Tech Briefs, volume 11, numbers 1-4
Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1986 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences
Tribological and mechanical characterization of ZnO nanowires
http://tartu.ester.ee/record=b2653173~S1*es
NASA Tech Briefs, July 1991
Topics include: New Product Ideas; NASA TU Services; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences
Plasmon Enhanced Photoconduction in Porphyrin-Gold Nanoparticle Assemblies
This thesis describes a series of experiments to both determine the origins of charge transport and enhanced photoconduction in metal nanoparticle arrays linked with zinc-porphyrin complexes, but to also determine the nucleation and growth mechanisms related to Ferroelectric Nanolithography (FNL) as a platform for hybrid devices. The development of test structures on glass substrates was undertaken to not only allow the study of the mechanisms controlling charge transport but the photoconduction of zinc-porphyrin linked gold nanoparticle (AuNP) arrays. In this study, the dominate charge transport mechanism was determined to be thermally assisted tunneling and the origins of enhanced photoconduction in these systems was attributed to three mechanisms: direct exciton formation in the molecules, hot electrons and a field effect (optical antenna) due to the excitation of surface plasmons. In the hope of developing a platform for hybrid devices, FNL was utilized to systematically vary the parameters that effect the deposition of metal nanoparticles through domain directed deposition on ferroelectric surfaces. The nucleation and growth mechanisms were determined through this work, where thevintegrated photon flux controlled the particle density and the interface between the particle and the ferroelectric surface determined the particles size. Finally, with the ability to control the deposition of AuNPs on a ferroelectric surface, hybrid devices of zinc-porphyrin linked AuNPs were realized with FNL
Carbon-Based Materials
New carbon materials with improved mechanical, electrical, chemical, and optical properties are predicted and considered to be very promising for practical application. Carbon-based materials in the form of films, fabrics, aerogels, or microstructural materials are known for their large surface areas and pore volumes, light weight, and a great variety of structural morphology. Such unique structures can then be employed for a variety of purposes, for example, the production of new electronic devices, energy storage, and the fabrication of new materials. Nowadays, clear understanding of carbon materials via several examples of synthesis/processing methodologies and properties characterization is required. This Special Issue, “Carbon-Based Materials”, addresses the current state regarding the production and investigation of carbon-based materials. It consists of 13 peer-reviewed papers that cover both theoretical and experimental works in a wide a range of subjects on carbon structures
Asymmetric tandem organic solar cells
Organic photovoltaics (OPVs) is an area that has attracted much attention recently as
a potential low cost, sustainable source of energy with a good potential for full-scale
commercialisation. Understanding the factors that determine the efficiency of such
cells is therefore a high priority, as well as developing ways to boost efficiency to
commercially-useful levels. In addition to an intensive search for new materials,
significant effort has been spent on ways to squeeze more performance out of
existing materials, such as multijunction cells. This thesis investigates double
junction tandem cells in the context of small molecule organic materials.
Two different organic electron donor materials, boron subphthalocyanine chloride
(SubPc) and aluminium phthalocyanine chloride (ClAlPc) were used as donors in
heterojunctions with C60 to create tandem cells for this thesis. These materials have
been previously used for solar cells and the absorption spectra of the donor materials
complement each other, making them good candidates for tandem cell architectures.
The design of the recombination layer between the cells is considered first, with
silver nanoparticles demonstrated to work well as recombination centres for charges
from the front and back sub-cells, necessary to avoid a charge build-up at the
interface. The growth conditions for the nanoparticles are optimised, with the tandem
cells outperforming the single heterojunction architecture.
Optical modelling is considered as a method to improve the understanding of thin
film solar cells, where interference effects from the reflective aluminium electrode
are important in determining the magnitude of absorption a cell can achieve. The use
of such modelling is first demonstrated in hybrid solar cells based on a SubPc donor
with a titanium oxide (TiOx) acceptor; this system is ideal for observing the effects
of interference as only the SubPc layer has significant absorption. The modelling is
then applied to tandem cells where it is used to predict the short-circuit current (Jsc)
generation of the sub-cells, which is not accessible experimentally. Current-matching
is then used to predict the Jsc of the complete tandem device.
As a support to the optical modelling, ellipsometry measurements of thin films of
ClAlPc are presented. These films of known thickness are analysed to extract the
complex refractive index for use in optical modelling calculations. A dependence of
the complex refractive index on film thickness and substrate is also noted.
Finally, the external quantum efficiency (EQE) technique is considered as applied to
solar cells, and an additional method is proposed to characterise current balancing in
asymmetric tandem cells under illumination. This technique is verified
experimentally by two separate sets of data
Cumulative index to NASA Tech Briefs, 1986-1990, volumes 10-14
Tech Briefs are short announcements of new technology derived from the R&D activities of the National Aeronautics and Space Administration. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This cumulative index of Tech Briefs contains abstracts and four indexes (subject, personal author, originating center, and Tech Brief number) and covers the period 1986 to 1990. The abstract section is organized by the following subject categories: electronic components and circuits, electronic systems, physical sciences, materials, computer programs, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences
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