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MIT researchers have developed a new application of carbon nanotubes that shows promise as an innovative approach to storing solar energy for use whenever it's needed. Storing the sun's heat in chemical form - rather than first converting it to electricity or storing the heat itself in a heavily insulated container - has significant advantages: in principle, the chemical material can be stored for long periods of time without losing any of its stored energy. The researchers created carbon nanotubes in combination with a compound called azobenzene. The resulting molecules, produced using nanoscale templates to shape and constrain their physical structure, and the concept that can be applied to many new materials. This material is vastly more efficient at storing energy in a given amount of space - about 10,000 times higher in volumetric energy density, making its energy density comparable to lithium-ion batteries, the researchers said. Ref.: Alexie M. Kolpak, Jeffrey C. Grossman, Azobenzene-Functionalized Carbon Nanotubes As High-Energy Density Solar Thermal Fuels, Nano Letters, 2011; 110705085331088 [DOI: 10.1021/nl201357n]

In a paper published in Nature Photonics, University of Toronto researchers report the first efficient two-layer solar cell based on colloidal quantum dots (CQD) to capture both visible and near-infrared rays. CQDs are nanoscale materials that can be tuned to respond to specific wavelengths of the visible and invisible spectrum. By capturing such a broad range of light waves - wider than normal solar cells - tandem CQD solar cells can in principle reach up to 42 per cent efficiencies. The best single-junction solar cells are constrained to a maximum of 31 per cent efficiency. (In reality, solar cells that are on the roofs of houses and in consumer products have 14 to 18 per cent efficiency.) The researchers expect that in five years, solar cells using the graded recombination layer paper will be integrated into building materials and mobile devices.

Scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have coaxed polymers to braid themselves into wispy nanoscale ropes that approach the structural complexity of biological materials.

Duke University engineer Nico Hotz has proposed a hybrid solar system in which sunlight heats a combination of water and methanol in a maze of tubes on a rooftop to produce hydrogen. The device is a series of copper tubes coated with a thin layer of aluminum and aluminum oxide and partly filled with catalytic nanoparticles. A combination of water and methanol flows through the tubes, which are sealed in a vacuum. Once the evaporated liquid achieves higher temperatures, tiny amounts of a catalyst are added, which produces hydrogen. This combination of high temperature and added catalysts produces hydrogen very efficiently, Hotz said. The resulting hydrogen can then be immediately directed to a fuel cell to provide electricity to a building during the day, or compressed and stored in a tank to provide power later. After two catalytic reactions, the system produced hydrogen much more efficiently than current technology without significant impurities, Hotz said. The resulting hydrogen can be stored and used on demand in fuel cells. "This set-up allows up to 95 percent of the sunlight to be absorbed with very little being lost as heat to the surroundings," he said. "This is crucial because it permits us to achieve temperatures of well over 200 degrees Celsius within the tubes. By comparison, a standard solar collector can only heat water between 60 and 70 degrees Celsius." Holtz performed a cost analysis, comparing a standard photovoltaic cell, a photocatalytic system, and the hybrid solar-methanol system.  He found that the hybrid system is the least expensive solution, with a total installation cost of $7,900 if designed to fulfill the requirements in summer. The paper describing the results of Hotz's analysis was named the top paper during the ASME Energy Sustainability Fuel Cell 2011 conference in Washington, D.C. Topics: Energy | Nanotech/Materials Science

Robots have been considered too unpredictable and dangerous to work alongside humans in factories, but improved technologies for artificial sensing and motion are leading to a new wave of safer robots. Last winter, NASA sent a humanoid robot dubbed Robonaut 2 (R2) to the International Space Station. R2, which has only a torso, sophisticated arms and fingers, and a head full of sensors, jointly developed by NASA and General Motors under a program to create a robot that could operate safely alongside humans. R2 uses a popular robotics technology called series elastic actuators in its joints. The actuators have an elastic spring component between the motor and the object the robot has to pick up. The actuators help the robot detect and control the force of its own movements. R2 is also covered in soft material in case of accidental collisions, and its head contains cameras so it can keep track of its human colleagues. In June, President Obama announced a $500 million federal investment in manufacturing technology (including $70 million for robotics). It represents another step in developing robots that can assist with repetitious or physically stressful assembly-line tasks without posing a safety risk.

(PhysOrg.com) -- Most of the invisibility cloaks that have been demonstrated to date conceal objects at frequencies that are not detectable by the human eye. Designing invisibility cloaks that can conceal objects from visible light has been more challenging due to the strict material requirements. But in a new study, researchers have fabricated a carpet cloak that can make objects undetectable in the full visible spectrum.

What would happen if we could generate power from our windowpanes? In this moving talk, entrepreneur Justin Hall-Tipping shows the materials that could make that possible, and how questioning our notion of 'normal' can lead to extraordinary breakthroughs.