MIT - Page 10

Researchers from MIT are developing a new solar cell made from graphene and molybdenum disulfide. They hope to achieve the "ultimate power conversion possible". These panels will be thin, light and efficient - in fact the researchers claim that for the same weight, the new panels will be up to a 1,000 times more efficient than silicon based panels.

A solar cell made from a single graphene sheet and a single molybdenum disulfide sheet will achieve about 1% to 2% efficiency. Silicon based cells achieve 15%-20%, but the researchers believe that stacking several layers together will boost the efficiency dramatically. The two layers together are just 1 nm thick, while silicon cells are hundreds of thousands times thicker.

MIT researchers developed a new system, based on ferroelectric materials and graphene, that uses plasmons wave control to interconnect between electronic devices and light wave devices (such as fiber optics and photonic chips). Current such interconnectors are relatively slow and are often a bottleneck in those systems.

The new hybrid-material device can control surface plasmons wave (oscillations of electrons confined at interfaces between materials). The waves operate at terahertz frequencies in this new device, which is considered ideal for next-gen computing devices.

Researchers from MIT use DNA to form nanoscsale shapes on graphene. The idea is to fold DNA to a specific shape and then deposit it on graphene. Using plasma lithography the shapes are then "etched" to the graphene sheet.

The researchers created the DNA structures using short synthetic DNA strands called single-stranded tiles. The tiles are assembled into shapes in a simple reaction. They can also be constructed using an approach called DNA origami, in which many short strands of DNA fold a long strand into a desired shape.

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).

UK patent consultancy CambridgeIP researched graphene patents and they say that the UK may be falling behind in the graphene race. CambridgeIP identified 7,351 graphene patents (and patent applications), and the leading countries by graphene patents are china (2,204), US (1,754) and Korea (1,160). The UK has only 54 graphene patent applications. Back in February the UK government announced a £50 million graphene drive, which aims to bring the country back to the forefront of graphene research.

The leading research institutes (by patents) are Sungkyunkwan University (Korea, 134), Zhejiang University (China, 97), Tsinghua University (China, 92), Rice University (US, 56), MIT (US, 34) and finally Manchester University (16).

Researchers from MIT developed a new solar (photovoltaic) cell that is made from several graphene sheets coated with nanowires. They say that this flexible and transparent cell could be made on the cheap.

The new solar panels use graphene as a replacement for ITO. The new electrode material is cheaper and provides several advantages over ITO: flexibility, low weight, mechanical strength and chemical robustness. The idea is to use a series of polymer coatings to modify the graphene properties, allowing them to bond a layer of zinc oxide nanowires to it, and then an overlay of a material that responds to light waves—either lead-sulfide quantum dots or a type of polymer called P3HT. Despite these modifications, graphene's innate properties remain intact.

The transparency of graphene coating to wetting is not as absolute as thought before. New research from MIT shows that for materials with intermediate wettability, graphene does preserve the properties of the underlying material. But for more extreme cases — superhydrophobic surfaces, which intensely repel water, or superhydrophilic ones, which cause water to spread out — an added layer of graphene does significantly change the way coated materials behave.

These extreme cases are of greatest interest. For example, coating a superhydrophobic material with graphene was seen as a possible way of making electronic circuits that would be protected from short-circuiting and corrosion in water.

Researchers from MIT and the Oak Ridge national Laboratory (ORNL) developed a promising new graphene-based membrane that can be useful to filter microscopic contaminants from water or for drug delivery. The membrane features high flux and tunability (i.e. it can quickly filter fluids but also be easily tunable to let certain molecules through while stopping others).

To develop the membrane, the team fabricated a 25 square millimeter graphene sheet using CVD. They managed to transfer the sheet to a polycarbonate substrate dotted with holes. They thought that the graphene will be totally impermeable, but experiments proved that salts can flow through the membrane.

Researcher from MIT discovered that graphene's basic properties (chemical reactivity, electrical conductivity and others) can vary dramatically based on the substrate material it is placed on. When placed on silicon dioxide, graphene becomes functionalized when exposed to certain chemicals, but when the substrate is boron nitride, the graphene is inert to the same chemicals.

The research, funded by the US Office of Naval Research, means that you can control the graphene ability to create chemical bonds - using different underlying materials.

MIT scientists have shown (in simulations) that nanoporous graphene can filter salt from water at a rate that is 2-3 orders of magnitude faster than today’s best commercial desalination technology, reverse osmosis (RO). This could lead to more efficient and smaller water desalination facilities.

Simulated nanoporous graphene filtering salt ions

The graphene is used as a membrane material that allows a flow of water with full salt refection via size exclusion. Other materials have been investigated for the same purpose, but the researchers say that graphene is the "ultimate" thin membrane as it's the thinnest one possible and as water flux across a membrane scales inversely with the membrane’s thickness.