Graphene sensors: introduction and market status - Page 57

Researchers developed a new way to detect protein-protein interactions using graphene. This kind of detection is used to monitor how a disease-related protein interacts with libraries of small peptides. The idea is to mix a tagged peptide with Graphene Oxide, which quenches the fluorescent signal from the pyrene-bound peptide when pyrene stacks onto its flat surface. Then, when adding the protein that needs to be tested you can find out whether it binds to the peptide by seeing whether the tagged peptide leaves the graphene oxide and the fluorescent signal returns.

Researchers from Europe developed a graphene-based device that can detect magnetic fields with a record sensitivity (down to the stray field of few magnetic molecules, better than the previous record of sensitivity by a factor of 100). The graphene was used like a spider web to chemically 'trap' the molecules and detect their magnetization at the same time. This new development may enable ultra-high density Spintronics memory and molecular sensors.

This device was built by depositing magnetic molecules on a graphene sheet. The molecules were synthesized so that they are suitable to graft the graphene lattice. The electrical measurements were performed at very low temperature (to limit the noise). The new device works pretty much like a spin valve, only it's much smaller.

Researchers from the University of Maryland (UMD) discovered that missing atoms in Graphene (called vacancies) act as tiny magnets (they have a magnetic moment) - and interact strongly with the electrons in graphene which carry electrical currents, giving rise to a significant extra electrical resistance at low temperature, known as the Kondo effect.

The researchers say that if you arrange the vacancies in the right order, you could get ferromagnetism. This could lead the way to nanoscale sensors of magnetic fields and could be useful in spintronics, too.

Researchers from the Rensselaer Polytechnic Institute got a $1 Million grant for a three-year study on a new coating (based on Graphene) for nanosensors that can be used for Oil or Gas exploration. The grant was given by the Advanced Energy Consortium.

Koratkar and colleagues are investigating how the flow of water, steam, or certain gasses over surfaces coated with carbon nanotubes or graphene can generate small amounts of electricity. The researchers seek to explain this phenomenon — which has been observed but is not yet fully understood — and use their findings to create tiny self-powered devices that travel through naturally occurring cracks deep in the earth and can help uncover hidden pockets of oil and natural gas.

IBM researchers are using graphene sheets to make photo(light) detectors. Graphene transports electrons very quickly, tens of times faster than current photo detectors (made by materials called III-V semiconductors), and can also absorb more light frequencies (visible and infrared).

It is already known that when metal contacts are deposited on graphene, electric fields are generated at the interface between the two materials. So the researchers took advantage of this field. Their device is a piece of multilayered graphene with metal contacts on top. When they shine light near the contact, the field separates the electrons and holes, and a current is generated.

Researchers at Columbia University in New York have made the first electrical-readout nanomechanical resonators made from graphene. The devices, which consist of vibrating sheets of graphene suspended over micron-sized trenches, could be used as highly sensitive, robust, mass detectors.

The researchers has made the graphene into a bridge-like resonators that vibrate at very high frequencies. The frequency changes each time a molecule is absorbed onto its surface.