Graphene sensors: introduction and market status - Page 55

Researchers from Harvard University developed a graphene-based electrically-tunable plasmonic mid-infrared antenna array. They say this device can be useful for multi-analyte sensors, reconfigurable meta-surfaces and optoelectronics devices.

This is the first time nanoantennas can be tuned to the mid-infrared part of the electromagnetic spectrum by simply applying a voltage. This works because a graphene sheet, placed in the nanogap of a dipole antenna, acts as an electrically tunable nano-circuit element.

Researchers from Japan's Advanced Institute of Science and Technology (JAIST) and the University of Southampton in the UK have developed a new way to fabricate ultra-fine graphene nanodevices using helium-ion microscopy. Usually this tool is used for sub-nanometer probing and high-resolution imaging, but this time they have used to it to selectively sputter graphene to create intricate nanoscale designs.

The researchers used their new technique to develop two devices: ultrathin suspended graphene nanoribbons for extremely sensitive gas molecular sensors and densely integrated graphene Quantum Dots for quantum information processing technologies.

Researcherrs from the University of California (UC Riverside) have finally (after almost a century of research) managed to find out what causes the low-frequency electronic 1/f noise (also known as pink noise or flicker noise). Using graphene sheets, it was found that 1/f noise is a surface phenomenon that shows up in situations that are thinner than 2.5 nm (at least for graphene).

Graphene was essential for this work because you can test for 1/f noise using a single sheet, and then add sheet after sheet (basically adding just one-atom to the thickness of the conductive material). This cannot be done with metal films.

Researchers from the ICFO, MIT, Max Planck and Graphenea have demonstrated that graphene is able to concert a single photon into several electrons (most materials generate a single electron in such a case). This means that Graphene is highly efficient in converting light to energy and can be an alternative material for light detection and energy harvesting.

The researchers used a single sheet of graphene and sent a known number of photos with different colors (energies). High energy photos (violet colored for examples) create more electrons than low energy photos (such as infrared colored ones).

Back in May 2011, a graphene research program (called FET Graphene Flagship) was shortlisted for one of two €1 billion EU research initiatives. Today we're happy to report that this project was indeed chosen by the European Commission. This is set to be a huge boost to graphene research and will hopefully accelerate commercialization of graphene based products. The EU will officially announce their decision next week (January 28).

The graphene flagship project is led by theoretical physicist Jari Kinaret at Chalmers University of Technology in Gothenburg, Sweden. The project will focus on developing graphene applications in the computing, batteries and sensor markets. It will also develop related materials. Back in 2011 it was reported that the project already includes over 130 research groups, representing 80 academic and industrial partners in 21 European countries.

Researcher from Northwestern University developed a new way to amplify signals in hybrid graphene oxide and CNT electrochemical sensors. They use a process called Magneto-Electrochemical Immunoassay to achieve that.

The researchers designed the new hybrid material to correlate the available metal ions with analyte concentration. They used magnetic particles encapsulated in inert coating of silicon dioxide which were later coated with gold (gold is chemically inert and bio-compatible). This process is efficient, fast and cost-effective.

Researchers from the University of Manchester and Aix-Marseille University developed a new optical device that can analyze a single molecule quickly, using Plasmonics (the study of vibrations of electrons in different materials). This could lead to virus detectors, fast and accurate athlete drug testing and explosive tracking in airports.

The device uses artificial materials with topological darkness that are highly sensitive to a single small molecule (this relies on topological properties of light phase). The artificial material is covered with graphene (which they say is one of the best materials that can be used to measure the sensitivity of molecules). Basically the device is like a single-molecule microscope.

Researchers from NASA are developing nano-sized sensors based on graphene. The potential applications are chemical sensors (detecting atmosphere atomic traces of oxygen and other elements) and strain sensors (for detecting strains in airplane wings or spacecrafts buses). The researchers are fabricating relatively large and high quality graphene using CVD and are now applying these to sensors.

The team wants to develop small, low mass and low-power chemical detectors that could measure the amount of atomic oxygen in the upper atmosphere - for its role in creating atmospheric drag (which can cause orbiting spacecraft to lose altitude prematurely and plunge to Earth). When graphene oxidizes it changes the electrical resistance - and this can be used to measure oxygen density. Graphene could also be used to measure methane, carbon monoxide and other gases.

Researchers from the National Cheng Kung University in Taiwan are studying graphene flakes, and creating conductive materials. Producing these flakes is much more simple than fabricating actual graphene sheets (they are doing it by chemically treating graphite). The researchers have been using these flakes to make regular paper conductive (simply by painting a solution with graphene flakes on it).

One of the first application the researchers are working on is strain sensors that can replace current sensors in oil and gas pipe lines, bridges, engines and airplanes to check the conditions of these items. They believe this could be one of the first real-world graphene applications.

Unlike graphene, graphene-oxide (GO) has a bandgap, but has poor electronic properties (due to disorganized arrangement of atoms). Now researchers from the University of Wisconsin—Milwaukee have developed a method to make ordered GO. They hope that this method will enable "ideal bandgap" carbon based devices to be used as transistors, sensors and optoelectronic devices.

The researchers made a device made from layers of oxygen-poor graphene sandwiched between layers of GO, and then annealed (heated) it. The resulting device (shown on the right of the image above) has a more complex and ordered structure (you can see this as the extra rings in the image).