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Graphene is the world's strongest, thinnest and most conductive material, made from carbon. Graphene's remarkable properties enable exciting new applications in electronics, solar panels, batteries, medicine, aerospace, 3D printing and more!
Recent Graphene news:
Researchers at the University of Aveiro in Portugal designed unique "tea bags" using a porous graphene oxide foam, which they say can help purify water by removing dissolved mercury. These foams demonstrate several significant advantages over existing water purification systems: they are reusable, simple to synthesize and should be easy to produce in bulk at a relatively low cost. The scientists add that they are also not affected by pH, which is beneficial since other sorbents often need the pH to be optimized, which drives up costs.
The scientists heated graphene oxide with ammonia to create a porous 3D material with a high surface area. After screening their materials for their ability to adsorb various toxic pollutants, the team chose to focus on mercury, one of the top three on the EU’s priority list of hazardous substances in water. The "tea bag" form was chosen due to the fact that the foam sometimes broke apart, and also to optimize contact with water.
Samsung researchers reportedly developed materials that can be used to double the capacity of Li-ion batteries. The key to the more efficient batteries is a new graphene-based cathode material. It is a new silicon cathode material "coded with high-crystalline graphene". As deployed in its lithium-ion batteries the new cathodes produce cells "with twice as much capacity as ordinary lithium-ion batteries," according to various reports.
This research presents a dramatic improvement of the capacity of lithium-ion batteries by applying a new synthesis method of high-crystalline graphene to a high-capacity silicon cathode. Samsung's team used silicon cathodes instead of graphite ones; this is not a novel approach, since many previous studies have also used it. The challenge, however, is that the silicon can expand or contract during the battery charging and discharging cycles. Samsung addressed this issue by creating a process to grow graphene cells directly on the silicon in layers that can adjust to allow for the silicon's expansion: "The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers. When paired with a commercial lithium cobalt oxide cathode, the silicon carbide-free graphene coating allows the full cell to reach volumetric energy densities of 972 and 700 Wh l-1 at first and 200th cycle, respectively, 1.8 and 1.5 times higher than those of current commercial lithium-ion batteries."
A collaboration between Bosch, the Germany-based engineering giant, and scientists at the Max-Planck Institute for Solid State Research yielded fascinating results, shown in a presentation during Graphene Week 2015. The researchers jointly created a graphene-based magnetic sensor 100 times more sensitive than an equivalent device based on silicon.
The research team used hexagonal boron nitride as substrate for the magnetic sensor, which is based on the Hall effect (a magnetic field that induces a Lorentz force on moving electric charge carriers, leading to deflection and a measurable Hall voltage). Graphene's high carrier mobility makes it useful in sensing applications, and the results achieved by the Bosch-led team confirm this. The presentation displaying the team's results showed that the worst case graphene scenarios roughly match a silicon equivalent. In the best case scenario, the result is a huge improvement over silicon, with much lower source current and power requirements for a given Hall sensitivity. In short, graphene provides for a high-performance magnetic sensor with low power and footprint requirements.
Researchers from the University of Exeter have designed a new method to produce graphene significantly cheaper and easier than previously production methods. The researchers claim that this high-quality, low cost graphene could pave the way for the development of the first truly flexible 'electronic skin', that could be used in robots.
The new method grows graphene in an industrial cold wall CVD system, a state-of-the-art piece of equipment recently developed by UK graphene company Moorfield. This nanoCVD system is based on a concept already used for other manufacturing purposes in the semiconductor industry. This new technique is said to grow graphene 100 times faster than conventional methods, reduce costs by 99% and have enhanced electronic quality. The research team used this new technique to create the first transparent and flexible touch-sensor that could enable the development of artificial skin for use in robot manufacturing as well as flexible electronics.
A team of scientists from the HZB Institute for Silicon Photovoltaics in Germany managed to increase the selectivity of graphene to various molecules in order to make more efficient sensors. The scientists were successful in electrochemically activating graphene and preparing it to host molecules that act as selective binding sites.
For this task, para-maleimidophenyl groups from an organic solution were grafted to the surface of the graphene. These organic molecules act as mounting brackets to which the selective detector molecules can be attached in the next step of the process. The attched graphene can then be employed for detecting various substances with a precise matching mechanism, similar to a "lock and key" paradigm. The "lock" molecules on the surface are highly selective and only absorb the matching "key" molecules.
Recent reports indicate the issue of a patent assigned to IBM, regarding a graphene resistor based tamper resistant identifier with contactless reading. The invention seems to relate to an identification system that is more immune to copying than traditional barcodes.
The method for creating this invention includes arranging an array of graphene resistors in parallel or series. The method also includes forming a unique identification code based on respective temperatures emanating from respective voltages output from the graphene resistors when the array of graphene resistors is in a powered state. Another aspect described in the patent application is an authentication apparatus that includes a plurality of graphene resistors with a bandgap voltage generation circuit or a bandgap current generation circuit connected to the plurality of graphene resistors for powering up the plurality of graphene resistors in the powered state.
A research team at the University of Michigan utilized Japanese paper cutting techniques, called kirigami, to create a new type of flexible conductor. The team believes that this technique may open up big possibilities for implantable medical devices, which have to flex and bend within the human body to work. Another option is gadgets that won't break when bending or flexing.
The first prototype of the kirigami stretchable conductor consisted of tracing paper covered in carbon nanotubes. The layout was quite simple, with cuts like rows of dashes. Later concepts were more intricate. for example, conductor sheets made out of graphene oxide, with etching cuts into the surface just a tenth of a millimeter long using laser beams and a plasma of oxygen ions and electrons.