Engineered nanoparticles that offer unique physical and chemical properties are rapidly flooding the market for commercial applications. The applications include, but are not limited to, cosmetic products, light emitting diodes, solid state display, drug delivery, disease diagnosis, nanoscale drug reformulations, MRI contrast agents, and new treatments. Predictions have indicated a dramatic increase in the market for nanotechnology and corresponding products to reach $1 trillion in 2012.As a result of the predicted increase in the use of NPs as components of consumer product, the presence of engineered nanoparticles in the environment has sparked human health safety concerns. NPs may be introduced to organisms by inhalation, intravenous (usually purposefully), ingestion, or absorption through the skin. It is projected that the total production of NPs will reach 58,000 tons/year in 2011-2020 which assures human exposure to NPs at the workplace, in food and drinking water, and wearable consumer products. This paper addresses the QD distribution when plants are exposed to NPs. Mung beans were incubated with aqueous solutions of quantum dots and allowed to grow for 21 days. The seedlings were sectioned and observed under the microscope to establish the locations of NPs with respect to the roots, stem, and leaves.

We clarify here certain aspects of the magnetic field (H) – temperature (T) phase diagram of YbMnO3, a hexagonal Rare-Earth manganite oxide in which two multiferroic ordered states – ferroelectricity and antiferromagnetism coexist at low temperature. Single crystals of YbMnO3 were carefully grown from a Floating Zone (FZ) at low speed, then oriented and studied at variable temperature and magnetic field. Magnetization and heat capacity measurement show features corresponding to the antiferromagnetic (AFM) ordering of Mn3+, and the rare earth Yb3+. We find that the ordering temperature of Mn3+ is independent of applied magnetic field up to 5T. However, contrary to previous reports in flux-grown crystals, we do not observe a complete suppression of Yb3+ order above 0.1T. Instead, we find that Yb3+ remains at least up to 1 T, suggesting a revision of our current understanding of the ordering mechanism of the Mn-Yb and Yb –Yb sub-lattices in this hexagonal structure.

The InAs/InGaAs DWELL solar cell grown by MBE is a standard pin diode structure with six layers of InAs QDs embedded in InGaAs quantum wells placed within a 200-nm intrinsic GaAs region. The GaAs control wafer consists of the same pin configuration but without the DWELL structure. The typical DWELL solar cell exhibits higher short current density while maintaining nearly the same open-circuit voltage for different scales, and the advantage of higher short current density is more obvious in the smaller cells. In contrast, the smaller size cells, which have a higher perimeter to area ratio, make edge recombination current dominant in the GaAs control cells, and thus their open circuit voltage and efficiency severely degrade. The open-circuit voltage and efficiency under AM1.5G of the GaAs control cell decrease from 0.914V and 8.85% to 0.834V and 7.41%, respectively, as the size shrinks from 5*5mm2 to 2*2mm2, compared to the increase from 0.665V and 7.04% to 0.675V and 8.17%, respectively, in the DWELL solar cells.The lower open-circuit voltage in the smaller GaAs control cells is caused by strong Shockley-Read-Hall (SRH) recombination on the perimeter, which leads to a shoulder in the semi-logarithmic dark IV curve. However, despite the fact that the DWELL and GaAs control cells were processed simultaneously, the shoulders on the dark IV curve disappear in all the DWELL cells over the whole processed wafer. As has been discussed in previous research on transport in QDs, it is believed that the DWELL cells inhibit lateral diffusion current and thus edge recombination by collection first in the InGaAs quantum well and then trapping in the embedded InAs dots. This conclusion is further supported by the almost constant current densities of the different area DWELL devices as a function of voltage.

We have developed a set of new electrochromic devices (ECDs) for special application goggles, whose color can be switched between transparent and a specific color mode, i.e. blue (B). This paper will discuss the design, film deposition, device assembly and characterizations of the color switchable lens. The ECD is composed of a layer of thin film conducting polymer poly (3,4-(2,2-dimethylpropylenedioxy)thiophene) (PProDOT-Me2), a layer of thin film inorganic oxide V2O5-TiO2, and a layer of ionic conductive electrolyte. The thin films are electrochemically deposited on ITO coated flexible plastic substrate. The whole device is packaged with an UV cured flexible film sealant. The goggle lens exhibit tuneable shade in visible light wave length (380-800nm), with a maximum contrast ratio at 580nm. Meanwhile, other unique properties include fast switching speed, low driving voltage, memory function (no power needed after switching, bistable), great durability, high flexibility, light weight, and inexpensiveness.

One-dimensional grating with 400 nm pitch was fabricated on a SiO2 glass surface. The grating was applied for detection of fluorescence excited by the electric field of the grating-coupled surface plasmon resonance and highly sensitive observation of fluorescence image by optical microscope. 40-times of fluorescence enhancement was obtained under optimal condition after our systematically investigating depth and duty ratio dependent behavior.

Hybrid solar cells based on conjugated polymers and colloidally synthesized inorganic nanoparticles have been recognized as an alternative to all-organic solar cells due to the intrinsically higher charge transport property in inorganic component. In this work, CdSe nanoparticles with different sizes, served as the electron acceptor, have been used together with poly(3-hexylthiophene) (P3HT) as the active layer for the hybrid solar cells. The power-conversion efficiency (ηp) of these devices strongly depends on the size of the CdSe nanoparticles, increasing from ηp ˜0.5% for 4.0 nm size nanoparticles to ηp ˜2.4% for 6.8 nm size nanoparticles under AM 1.5 G solar illumination. Furthermore, the devices also exhibit an unusual initial aging period when exposed to the air, which results in a significant enhancement in the short-circuit current, open-circuit voltage and power conversion efficiency.

Applications of nanoscience in the non-traditional classroom have successfully exposed students to various methods of research with applications to micro- and nano-electronics. Activities obtained from the NanoSense website associated with current global energy and water concerns are solid examples. In this regard, all 36 students in the 2008-2009 Science Research Program (SRP) prepared and delivered individual and group lesson plans in addition to their authentic, year-long research projects. Two out of 36 students selected nanoscience based projects in preparation for science fair competition in 2009. Additionally, preliminary research was conducted while participating in the Center for Research on Interface Structures and Phenomena (CRISP) Research Experience for Teachers (RET) Program in summer 2008 which supported the idea of developing a photolithography kit. This kit is intended to introduce high school students to the fundamentals of photolithography. In this paper, the design, implementation and feasibility of this kit in the high school classroom is described as well as details involving individual and group nanoscience based projects. Supporting educational models include self-regulated learning (SRL) concepts; situated cognition; social constructivism; Renzulli's (1977) enrichment triad and Types I – III inquiry enrichment activities.

New materials and structures have been developed for efficient organic solar cells, dye-sensitized solar cells (DCSs) and organic thin-film solar cells (OPVs). Some strategies for achieving high photon-to-electricity conversion efficiency in these solar cells are discussed, focusing on nanostructured materials. In the case of DSCs, unlike TiO2 nanoparticles, TiO2 nanotubes with suitable dimensions are expected to work as efficient light scatterers as well as to give large surface areas for charge separation. A strategy for designing triarylamine-functionalized ruthenium dyes, which display the high efficiency, is also proposed. Furthermore, OPVs based on donor/acceptor (D/A) block copolymers are discussed, focusing on the phase separation of donor and acceptor segments and their domain sizes.

In many industrial fields, structural materials play a key role in the increase of performance, but new requirements in terms of energy saving, safety, materials economy… lead to more stringent requirements on materials properties. The two usual strategies –microstructure optimisation and shape optimisation-, which act at two different scales, the micrometer scale and above the centimetre scale, become less and less efficient with this new strong demand for multi-functional properties. The largely unexplored millimetre scale, domain of the so called “structural materials”, is a possible answer. Structural materials benefit of an extra degree of freedom well suited for multi-functionality: they allow using combination of materials from different classes, allow geometrical optimisation, and can be naturally integrated in structures such as sandwiches and various stiffened plate geometries. The price to pay for this extra-richness is the extraordinary wide variety of potential solutions to investigate for a given problem. Hence modelling plays a crucial role for selecting and optimising such innovative materials. This paper is an overview of a project, named MAPO (“Materiaux Poreux”), aiming at designing high-temperature materials with acoustical and structural properties.

We study pressure-induced structural phase transition of carbon nanotubes using the constant-pressure tight-binding molecular-dynamics simulation. The systems studied are nanotube bundles composed of (6,6) armchair nanotube and/or (7,4) chiral nanotube, which are reported to be the nanotubes relatively abundant in experimentally purified sample. We find that the nanotube bundles transforms into a new phase that consist of graphitic ribbons and diamond blocks, “graphitic nanoribbon solid”. It is also found that sp 3-rich phases obtained from the armchair nanotubes possess an anisotropic network and have high hardness which is comparable to that of cubic diamond. In the case of the bundles containing chiral nanotubes, on the other hand, amorphous diamond phase is obtained. Based on the local-density approximation in the density-functional theory, we also investigate the energetics and electronic structure of some of new carbon phases obtained in the molecular-dynamics study.

A 2-D numerical circuit model is used to analyze the impact of shunts on basic performance parameters of a CdTe thin-film module. A numerical estimate of module-efficiency loss in the worst-case scenario due to shunts of different severity and fractional module area is presented. It is shown that absolute module-efficiency loss Δη (%) varies in systematic fashion with these shunt parameters. Estimates of Δη based on simple area-weighted efficiency are typically low by 3-4 times. Furthermore, the distribution pattern of shunts over the module plays a significant role in the module loss. A reliable parameter P to characterize the distribution of shunts is introduced, and its effect on module-efficiency loss, as well as individual-parameter (FF, VOC and JSC ) losses, is shown. Furthermore, higher transparent-conductive-oxide (TCO) sheet resistance is shown to increase shunt isolation and consequently mitigate the efficiency decrease.

In order to continuously improve the performances of microelectronics devices through scaling, SiO2 is being replaced by high-k materials as gate dielectric; metal gates are replacing poly-Si. This leads to increasingly more complex stacks. For future generations, the replacement of Si as a substrate by Ge and/or III/V material is also considered. This also increases the demand on the metrology tools as a thorough characterization, including composition and thickness is thus needed. Many different techniques exist for composition analysis. They usually require however large area for the analysis, complex instrumentation and can be time consuming. EDS (Energy Dispersive Spectroscopy) when coupled to Scanning Electron Microscopy (SEM) has the potential to allow fast analysis on small scale areas.

In this work, we evaluate the possibilities of EDS for thin film analysis based on an intercomparison of composition analysis with different techniques. We show that using proper modeling, high quality quantitative composition and thickness of multilayers can be achieved.

Many programs promote professional development for teachers in laboratory settings. In fact, some research has shown these experiences can improve student achievement. However, it is unclear what aspect of the laboratory experience helps bring about this effect. In order to ensure all teachers participating in Stanford's Research Experiences for Teachers program received maximum benefit from the laboratory experience, supplementary seminars were delivered that emphasized a variety of skills and tasks required of career scientists and engineers. Teacher feedback indicates that participants found these seminars valuable and that they would prefer additional time for peer interaction and curriculum development.

For a formation of metal hydride of MgH2 or AlH3 under room temperature and ambient pressure, the cathode electrodes of metal and lithium hydride are electrochemically charged with Li anode electrodes in the system of Li-ion extraction. For MgH2 formation, the VC (Voltage-Composition) curve of Mg + 2LiH during charge shows a plateau voltage at 0.6 V until the final composition of 1.05 Li extraction. After charge MgH2 phase is observed by the XRD measurement. Therefore MgH2 is produced by the electrochemical charge from Mg and LiH. For AlH3 formation, Al + 3LiH is charged until the final composition of 0.6 Li at a plateau voltage of 0.8 V which corresponds to the reaction between Al and LiH for the formation of AlH3. In the XRD profile after charge AlH3 phase is not detected although the intensities of Al and LiH decrease compared with these before charge, which suggests the reaction leading to the formation of AlH3.

This paper describes studies of patterned arrays on glass surfaces and their use as spatially separated reactors for in situ synthesis of DNA using an inkjet synthesizer. Photolithographic methods were employed to fabricate arrays composed of homogenous circular features containing a hydroxyl-terminated silane coupled to the surface of the glass via a siloxane bond. Features are embedded within a background matrix composed of a fluorosilane attached to the glass. Due to the differential wettability of the two silanes, whereby the hydroxyl-terminated silane and fluorosilane are hydrophilic and hydrophobic respectively because of their head groups, the patterned circular features are able to constrain liquid within a defined site. The silanization result was analyzed using X-ray photoelectron spectroscopy (XPS) to optimize silanization time and solvent. Synthesis was then performed using a custom-built inkjet system using phosphoramidite chemistry. Base-by-base analysis using fluorescent labeling showed consistent coupling efficiency on synthesis of a 50-mer homopolymer.

The tremendous expansion and the relative avidity for silicon of the solar cell technology has resulted in a dramatic change of the polysilicon industry structure. While in the past the polysilicon was manufactured almost exclusively for the semiconductor industry, in 2008 around 67% of the total production was consumed by the solar industry. The consequence is that while in 2000 virtually only 7 companies supplied all the polysilicon consumed worldwide, in 2008 there were 11 major suppliers and numerous new ventures entering this market.Based on this in 2006 CENTESIL was founded as a new private-public partnership venture to deal with the polysilicon research. For it, a pilot plant is in advanced state of construction that has been preceded of some laboratory-size implementations. The pilot plant is designed for a production capacity of 60 kmol of trichlorosilane per day and 2 t of purified silicon per batch at the CVD reactor. The purpose is to allow the photovoltaic companies worldwide to count with an independent research centre to help them to establish their own polysilicon plant.The R&D activities already carried out by CENTESIL and the present status of the project are discussed in the paper.

We propose a wavelength-dependent figure of merit for transparent conducting nanotube networks, composed of the sheet resistance and the optical density. We argue that this would be more useful than previous suggestions, because it relies on more realistic assumptions regarding the optical parameters of real nanotubes.

It is clear that in the next ten years major changes will be required in our liquids for transportation energy scenario. These changes are driven by two major factors. The first is the desire to achieve 'energy independence' and the second is the desire to achieve an 'environmentally friendly' fuel supply. These two forces will dominate energy research and development in the near future. This presupposes that the lack of viable hydrogen storage materials and the long-range electric vehicle materials will continue to be limiting the hydrogen and electric vehicle technology. The DOE recently reported that the available amounts of heavy hydrocarbons (tars, coal and shale oils) in North America (United States, Canada and Mexico) are sufficient for 500 years at current rates of usage. However, these sources must be converted to liquid transportation fuels in an environmentally favorable manner. Also, promising sources of sustainable liquid transportation fuels maybe found in growing algae and converting the contained lipids to biodiesel. In this presentation we discuss recent development in both areas that promise a smooth transition from conventional to the use of sustainable transportation fuel sources.

A scenario analysis was performed for microbial effect on the performance assessment (PA) of the high-level radioactive waste disposal system. Based on review of recent literature on PA and some results of our experiment, possible scenario of microbial effects on the Japanese high-level radioactive waste disposal system were analyzed. The result of the analysis shows that the microbial effect on groundwater evolution, which is caused by the microbial redox reaction, is one of the most important issues in assessing PA. The evolution not only affects radionuclide migration but also the life-time of metal overpack corrosion.

To assess the microbial effect on groundwater evolution, a numerical estimation code is required, with reliable parameters for analysis of microbial activities used in the code. A biological parameter database has been developed to give the growth and metabolism of the six typical microbial groups to be used in the estimation code. For this purpose, about 573 data from 95 papers were examined to obtain effective data for disposal. The database is composed of significant data like specific growth rate, maximum growth rate, constant decay rate, and experimental condition for model assessment.

In this article, an alternative strain-free growth mode is presented where GaAs coupled-quantum dots are grown on lattice matched AlGaAs. The coupled quantum dots were grown at 550 °C in a molecular beam epitaxy system. The GaAs quantum dots were characterized by using a photoluminescence technique and an atomic force microscope. The photodetector was fabricated into normal incident configuration and photoconductivity spectra were measured covering the mid-infrared spectrum of 2.0 – 8.0 micron (intersubband transitions) and the visible-near-infrared spectrum of 0.5 – 0.9 micron (interband or exciton transitions). The photoresponse spectra in mid-infrared spectral range were found to exist at temperatures lower than 80 K, while the photoresponse spectra in the visible-near-infrared range were observed at temperatures as high as 300 K.