Energy generation - Page 5

Researchers from the University of Nebraska-Lincoln developed a chemical process to produce graphene nanoribbons (GNRs). This bottom-up method can be used to produce very narrow GNRs (2 nanometers wide). The researchers say it is easy to scale up their process.

The team is now testing their ribbons for applications in electronics, gas sensors and solar cells. The electronic properties of their GNRs can be tuned by changing the synthetic conditions.

European researchers developed, produced and characterized a photovoltaic device based on a combination of titanium oxide and graphene as charge collector and Perovskite as sunlight absorber. This PV cell can be produced at low temperatures and is very efficient at 15.6% - higher than graphene combined with silicon.

Perovskite structures absorb sunlight very effectively, and this new development is a milestone for the progress of perovskite solar cells.

Researchers from the SLAC lan in Stanford University developed a new method to make 2D material molybdenum diselenide or MoSe₂ that has possible applications in photoelectronic devices, such as light detectors and solar cells, and perhaps also novel electronic devices.

This is the first time single-layer MoSe₂ has been efficiently produced. The method they developed is based on molecular beam epitaxy, and starts with molybdenum and selenium, which are heated in a vacuum chamber until they evaporate. The two elements combined as a thin film. By tweaking the process, they managed to create thin films - one to eight atoms thick. Those sheets were grown on graphene substrates. 

Researchers from Germany's HZB Institute for Silicon Photovoltaics discovered that graphene retains its impressive conductive properties even when coated with a thin silicon film. The researchers hope this discovery will lead into graphene adoption in thin-film photovoltaics.

The researchers grew a graphene sheet on a copper, and transferred it to a glass substrate. Then they coated it with a silicon layer. They tested both amorphous silicon (a-Si) and poly-crystalline silicon. Measurements of carrier mobility using the Hall-effect showed that the mobility of charge carriers within the embedded graphene layer is roughly 30 times greater than that of conventional zinc oxide based contact layers.

Researchers from Manchester University have demonstrated that graphene can be used to investigate how light interacts (via plasmon resonance) with gold nanostructures of different shape, size and geometry. This could lead to more efficient solar cells and photo detectors.

The researchers explain that when light shines on a metal particle smaller than the wavelength of the light, the electrons in the particle start to move back and forth along with the light wave. This causes an increase in the electric field at the surface of the particle. When two such metal particles are close to each other, the oscillating electrons in the two particles interact with each other, forming an even higher electric field which results in a coupling between the two particles. Up until now it was difficult to experimentally observe and measure the magnitude of this coupling and electric field.

The Korean Intellectual Property Office posted some interesting figures today. They report that Korean companies are securing essential patents related to the commercialization of graphene - and several companies are making inroads into graphene production and manufacturing transparent graphene-based displays.

Between 2005 and June 2013 a total of 2,921 graphene-related patents have been applied for in Korea, and the rate is accelerating quickly. 93% of those patents have been applied for by Korean individuals and organizations.

Researchers from Michigan Technological University developed a new "3D Graphene" material that can be used to replace platinum used in dye-sensitized solar cells (DSSC). The new material is cheap and easy to make, and using it as an electrode the researcher fabricated a DSSC cell that has an energy efficiency of 7.8% (conventional platinum-electrode based solar cell achieve 8%).

To synthesize this new material, the researchers combined lithium oxide with carbon monoxide in a chemical reaction that forms lithium carbonate (Li2CO3) and the honeycomb graphene. The Li2CO3 helps shape the graphene sheets and isolates them from each other, preventing the formation of garden-variety graphite. It's easy to remove the Li2CO3 particles using acid.

Researchers from Korea's Ulsan National Institute of Science and Technology (UNIST) developed a simple and low-cost way to dope graphene nanoplatelets (GNPs) with Nitrogen. These new materials may prove useful for dye-sensitized solar cells and fuel cells.

The researchers used dry ball-milling and they say that this is an efficient way to chemically modify the graphene flakes. This is more useful than current ways (most commonly the Harber-Bosch process, which requires extreme pressure and temperature conditions).

Researchers from the University of Vienna managed to assemble a new structure of high-quality metal silicides (nickel, cobalt and iron) coated with a graphene sheets. Using angle-resolved photoemission spectroscopy (ARPES), the researchers studied the electronic properties of this new material.

It was found that the graphene protects the silicides against oxidation, while barely interacting with the silicides themselves. The unique properties of the graphene are widely preserved. This means that this new composite material is a good way to incorporate graphene with existing metal silicide technology, which will hopefully enable the usage of graphene in applications such as semiconductor devices, spintronics, photovoltaics and thermoelectrics.

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.