Energy generation - Page 8

Researchers from the University of Science and Technology of China developed a new robot that's made by layering a polyethylene film onto a glass layer and an adding a layer of graphene that is used to convert photothermal energy from infra red light. The robot can pick, move and drop objects. Such a design may be useful for surgery, for example. It can also inspire the design of transparent artificial muscles.

The team prepared the actuator by layering a polyethylene film onto a glass layer. On top of this, they added a graphene layer, which can absorb infrared light and convert this energy into heat with a high efficiency. The graphene - a sheet of carbon atoms one atom thick - also combines high transparency with strong mechanical performance. A strip of graphene on polyethylene that was 3mm by 12mm was then cut out and peeled off the glass, after which the strip curled up.

It's been known for a long time that Graphene generates current from light. Up until now everybody assumed it was due to the photovoltaic effect, but a new research by MIT researchers shows that this is not true. They found that light on graphene causes it to develop two regions with different electrical properties which creates a temperature difference.

This "hot-carrier response" is what generates the current - and it's very unusual - it's been observed before but only under very low temperature or when using intense high power laser. The reason for this unusual thermal response is that graphene is the strongest material known. In most materials, superheated electrons would transfer energy to the lattice around them. In the case of graphene, however, that’s exceedingly hard to do, since the material’s strength means it takes very high energy to vibrate its lattice of carbon nuclei — so very little of the electrons’ heat is transferred to that lattice.

MIT announced the creation of the MIT/MTL Center for Graphene Devices and Systems (MIT-CG). This is an interdepartmental center which is part of the Microsystems Technology Laboratories (MTL) with an aim to bring together MIT researchers and industrial partners to advance the science and engineering of graphene-based technologies.

The MIT-CG will research the basic physical properties of graphene and will also explore advanced technologies and strategies that will lead to graphene-based materials, devices and systems for a variety of applications (including graphene-enabled systems for energy generation, smart fabrics and materials, radio-frequency communications, and sensing).

A new study finds that by combining graphene with metallic nanostructures, there was a 20-fold enhancement in the amount of light the graphene could harvest and convert into electrical power. The team (which included last year's Nobel Prize-winning scientists Andre Geim and Kostya Novoselov) says that these new graphene cell devices can be incredibly fast - tens or potentially hundreds of times faster than communication rates in the fastest Internet cables currently in use. The problem was the cell devices' low efficiency as graphene absorbs very little light (around 3%).

They now found that this problem can be solved by combining graphene with tiny metallic structures known as plasmonic nanostructures, which are specially arranged on top of graphene. The light-harvesting performance of graphene was boosted by 20 times without sacrificing any of its speed.

Researchers from the Rensselaer Polytechnic Institute developed a new way to harvest energy from flowing water using graphene. This could lead the way towards self-powered microsensors used for oil exploration. The team demonstrated the harvesting of 85 nanowatts of power from a sheet of graphene measuring .03 millimeters by .015 millimeters.

It is the first research paper to result from the $1 million grant awarded in 2010 by the Advanced Energy Consortium.

Electronics.ca published a new market research report (titled Graphene: Technologies, Applications, and Markets) in which they forecast that graphene-based product sales will reach $67 million in 2015 and $675 million in 2020. The compound annual growth rate (CAGR) between 2015 and 2020 will be 58.7%.

Here's how they see the market share of different graphene applications:

• Capacitors: growing from $26 million in 2015 to $340 in 2020
• Structured materials: $17.5 million in 2015 and $91 million in 2020.
• The display market: nothing in 2015 to $43.8 million in 2020.
• The photovoltaics: $7.5 million in 2015 to $35 million in 2020.  
• The thermal management market: $15 million in 2015 to $22.5 million in 2020.
• Other products: $1 million in 2015 to $142.8 million in 2020.

Researchers from MIT developed a new way to use Graphene as an electrode for organic solar cells. The biggest problem with using Graphene in such a device was getting the material to adhere to the panel. Graphene repels water, so typical procedures for producing an electrode on the surface by depositing the material from a solution won’t work.

The team tried a variety of approaches to alter the surface properties of the cell or to use solutions other than water to deposit the carbon on the surface, and they found that doping the surface — that is, introducing a set of impurities into the surface — changed the way it behaved, and allowed the graphene to bond tightly. As a bonus, it turned out the doping also improved the material’s electrical conductivity.

Researchers from MIT have created a new organic solar cell that uses transparent Graphene based electrodes. The new electrodes are made by using AuCl₃ to dope graphene, which makes it more durable and more efficient.

Transparent solar cells are useful because they can be used inside windows, and researchers are looking to replace ITO that is used in current designs.

Researchers from Case Western Reserve University and other institutions have created graphene-polymer solar cells that can be manufactured using solution processing. Polymer based solar cells are thought to be cheaper than silicon based ones, but less efficient. Using carbon nanotubes can increase the efficiency by increasing the surface/interface area and charge separation and transport.

The researchers say that Graphene has the highest room-temperature mobility for electron and hole transport among all known carbon nanomaterials and its one-atom thick. A 2-D carbon network provides a much higher specific surface area (hence, a larger interface in a polymer matrix) than carbon nanotubes

Researchers from the University of Southern California is using Graphene as a transparent flexible conductive layer for organic solar cells (OPVs). OPVs are considered as a cheap way to make solar cells, because they are easy to make, they weight very little and can be flexible. The USC team has produced graphene/polymer sheets ranging in sizes up to 150 square centimeters that in turn can be used to create dense arrays of flexible OPV cells.

Graphene marks a major advance over another OPV design, one based on Indium-Tin-Oxide (ITO) in at least one crucial area: the ITO cells fails at a very small angle of bending, while the graphene based cells remained operational and sustained repeated bending with more than twice the stress angle of the ITO solar cells.