MIT team uses graphene to create improved membranes

Jun 29, 2017

Researchers from MIT have fabricated a functional dialysis membrane from a sheet of graphene. The team’s membrane is able to filter out nanometer-sized molecules from aqueous solutions up to 10 times faster than state-of-the-art membranes, with the graphene itself being up to 100 times faster. The graphene membrane is also very thin; It's less than 1 nanometer thick, while the thinnest existing membranes are about 20 nanometers thick.

MIT's graphene membrane image

Dialysis can be generally described as the process by which molecules filter out of one solution by diffusing through a membrane, into a more dilute solution. The most recognizable form is hemodialysis, which removes waste from blood, but scientists also use dialysis for many other applications, like purifying drugs, removing residue from chemical solutions, and more, typically by allowing the materials to pass through a porous membrane.

Graphene and quantum dots enable a unique CMOS-integrated camera

May 30, 2017

Researchers from the ICFO have developed the first graphene-QDs-CMOS integrated camera, capable of imaging visible and infrared light at the same time. The camera may be useful for many applications like night vision, food inspection, fire control, vision under extreme weather conditions, and more.

The imaging system is said to be based on the first monolithic integration of graphene and quantum dot photodetectors, with a CMOS (complementary metal-oxide semiconductors) read-out integrated circuit. The implementation of such a platform in applications other than microcircuits and visible light cameras has been impeded by the difficulty to combine semiconductors other than silicon with CMOS, an obstacle that has been overcome in this work.

Graphenea and U of Hamburg team upscale high-quality graphene devices

May 07, 2017

Researchers from the University of Hamburg and Graphenea have succeeded in upscaling high-quality graphene devices to the 100-micron scale and beyond. By perfecting CVD graphene production, transfer and patterning processes, the team managed to observe the quantum Hall effect in devices longer than 100 micrometers, with electronic properties on par with micromechanically exfoliated devices.

Graphenea upscales graphene devices

The work started from graphene grown by chemical vapor deposition (CVD) on a copper substrate. Since graphene on metal is not useful for applications in electronics, the material is usually transferred onto another substrate before use. The transfer process has proven to be a challenge, in many cases leading to cracks, defects, and chemical impurities that reduce the quality of the graphene.

Graphenea, Nokia and IEMN-CNRS collaborate to create high-frequency graphene transistors on flexible substrates

Feb 21, 2017

Scientists from IEMN-CNRS, Graphenea, and Nokia have demonstrated flexible graphene transistors with a record high cut-off frequency of 39 GHz. The graphene devices, made on flexible polymer substrates, are stable against bending and fatigue of repeated flexing.

The graphene field effect transistor (GFET) is made from high quality CVD grown graphene with a carrier mobility of ~2500 cm2 V-1 s-1 on a flexible Kapton substrate with a thin alumina dielectric spacer in the channel region. The use of such sophisticated and optimized materials leads to the record high frequency performance as well as stability against bending. The GFET reportedly continues to operate even after 1,000 bending cycles and can be flexed to a radius of 12 mm with a cutoff frequency shift of up to 10%.

A novel doping method could open the door to FLG use as transparent conducting electrodes

Feb 15, 2017

Researchers from King Abdullah University of Science and Technology (KAUST), in collaboration with the Georgia Institute of Technology, have recently demonstrated a simple, solution-based, method for surface doping of few-layer graphene (FLG) using novel dopants (metal-organic molecules) that show a minimal effect on the optical transmission as compared to other dopants like metal chlorides.

This work investigates the effect of dopant strength and dosage on the electronic and electrical transport properties of doped FLG. Moreover, It reveals fundamental differences between the doping results in single layer graphene and few-layer graphene. The study focused on few-layer CVD graphene, rather than single-layer CVD graphene, a somewhat less common area of research to date.

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