Graphene enables researchers to control infrared and terahertz waves

Researchers from the University of Geneva (UNIGE) in Switzerland and the University of Manchester in the UK have found an efficient way to control infrared and terahertz waves using graphene. "There exist a class of the so-called Dirac materials, where the electrons behave as if they do not have a mass, similar to light particles, the photons," explains Alexey Kuzmenko, a researcher at the Department of Quantum Matter Physics in UNIGE's Science Faculty, who co-conducted this research together with Ievgeniia Nedoliuk.

The interaction between graphene and light suggests that this material could be used to control infrared and terahertz waves. "That would be a huge step forward for optoelectronics, security, telecommunications and medical diagnostics," points out the Switzerland-based researcher.

Unique device that combines graphene and boron nitride can switch from superconducting to insulating

Researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have designed a graphene device that switches from a superconducting material to an insulator and back again to a superconductor — all with a flip of a switch. The team shared that the device exhibits this unique versatility while being thinner than a human hair.

Graphene and hBN device moves from insulating to superconducting imageViews of the trilayer graphene/boron nitride heterostructure device as seen through an optical microscope. The gold, nanofabricated electric contacts are shown in yellow; the silicon dioxide/silicon substrate is shown in brown and the boron nitride flakes

"Usually, when someone wants to study how electrons interact with each other in a superconducting quantum phase versus an insulating phase, they would need to look at different materials. With our system, you can study both the superconductivity phase and the insulating phase in one place," said Guorui Chen, the study's lead author and a postdoctoral researcher in the lab of Feng Wang, who led the study. Wang, a faculty scientist in Berkeley Lab's Materials Sciences Division, is also a UC Berkeley physics professor.

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.

Supercomputer models graphene-water interaction

Researchers at the New Jersey Institute of Technology (NJIT) used the Comet supercomputer at the San Diego Supercomputer Center (SDSC), located at the University of California San Diego, to create detailed simulations of graphene-water interactions, to determine if graphene is a good candidate for delivering medicine to a specific part of the body.

Cross-sectional view of seven graphene flakes in a water droplet imageA simulation done using SDSC’s Comet supercomputer shows a cross-sectional view of seven graphene flakes in a water droplet, and that the multi-layered graphene eventually merges together. Credit: Solanky et al.

While graphene has been extensively studied for many years in water-based solutions, especially in the biomedical sciences field, researchers say they still need to better predict the surface traits of such two-dimensional materials when exposed to water or liquids containing water.

Graphene and bacteria combine to create a powerful electrocatalyst

Researchers from KAUST show that microbes and nanomaterials like graphene can be used together to form a biohybrid material that performs well as an electrocatalyst. The team says that such materials could be used in the solar-powered production of carbon-free fuels and several other green-energy applications.

Graphene and bacteria to produce clean energy

A process called the oxygen-evolution reaction (OER) is at the heart of many clean energy technologies. In the case of solar-fuel production, for example, the OER enables the use of solar electricity to split water molecules into oxygen and hydrogen, producing clean hydrogen that can be used as a fuel. Currently, rare and expensive metals are used as OER electrocatalysts. However, graphene-based biohybrid materials could make an inexpensive, eco-friendly alternative, as the team at KAUST has shown.