Researchers produce graphene by mixing oxidized graphite with bacteria

Researchers at the U.S-based University of Rochester, along with colleagues at Delft University of Technology in the Netherlands, have designed a way to produce graphene materials using a novel technique: mixing oxidized graphite with bacteria. Their method is reportedly a more cost-efficient, time-saving, and environmentally friendly way of producing graphene materials versus those produced chemically, and could lead to the creation of innovative computer technologies and medical equipment.

Bacterially-made graphene is faster, cheaper and better imageFrom left to right:graphite (Gr), graphene oxide (GO), microbially‐reduced graphene oxide (mrGO), and chemically‐reduced graphene oxide (crGO)

"For real applications you need large amounts," says Anne S. Meyer, an associate professor of biology at the University of Rochester. "Producing these bulk amounts is challenging and typically results in graphene that is thicker and less pure. This is where our work came in". In order to produce larger quantities of graphene materials, Meyer and her colleagues started with a vial of graphite. They exfoliated the graphite-shedding the layers of material-to produce graphene oxide (GO), which they then mixed with the bacteria Shewanella. They let the beaker of bacteria and precursor materials sit overnight, during which time the bacteria reduced the GO to a graphene material.

Graphene biosensors detect cancer causing bacteria

Researchers at Osaka University have invented a graphene-based biosensor to detect bacteria such as those that attack the stomach lining and that have been linked to stomach cancer. When the bacteria interact with the biosensor, chemical reactions are triggered which are detected by the graphene.

Graphene-based sensors detect cancer-causing bacteria image

To enable detection of the chemical reaction products, the researchers used microfluidics to contain the bacteria in extremely tiny droplets close to the sensor surface.

Emberion to launch a VIS-SWIR graphene photodetector

Graphene Flagship partner, Emberion, will be launching a VIS-SWIR graphene photodetector at Laser World of Photonics, from 24 to 27 June in Munich, Germany. The linear array covers a wide spectral range, detecting wavelengths from the visible at 400nm into the shortwave infrared up to 1,800nm. Traditionally, it would require both silicon and InGaAs sensors to image across this wavelength range.

Emberion to launch a VIS-SWIR graphene photodetector image

Emberion estimates that replacing a system using silicon and InGaAs sensors with its graphene photodetector would result in a 30% cost reduction.

Mitsubishi develops MWIR and LWIR graphene-based sensors

Mitsubishi has reportedly developed graphene-based MWIR sensors with extraordinarily high sensitivity. Thanks to an internal graphene FET gain, the responsivity is said to be 10 times higher than that of quantum-type IR sensors with no internal amplification. Mitsubishi uses graphene FET and leverages its high electron mobility.

Mitsubishi graphene sensors image

Other than a graphene-based FET, reports suggest that there is "a light-amplifying part" that produces photoelectrons and photoholes and is placed under the graphene. At a very low temperature of, for example, 80K, the responsivity increases even more, by a factor of 100x.

Inorganic dopants inspire n-type graphene transistor progress

Researchers in India have made graphene field-effect transistors based on discrete inorganic structures that reportedly work for over 10 months. The approach has led them to produce a graphene logic inverter that is stable in ambient conditions.

Inorganic dopants inspire n-type graphene transistor progress image

Conventional electronics are silicon based, due to the ease of doping silicon with either electrons or holes. These two forms of silicon, n- and p-type, are the building blocks of electronic devices. However, it isn’t possible to make silicon electronics on the nanoscale, so many researchers are turning to materials like graphene.