Renewable Energy Needed to Drive Uptake of Electric Vehicles ~ Queensland University

Queensland Elec Vehicle rd1704_cars

Plugging into renewable energy sources outweighs the cost and short driving ranges for consumers intending to buy electric vehicles, according to a new study.

Queensland University of Technology Postdoctoral Research Fellow Dr Kenan Degirmenci, from QUT Business School, said environmental performance – or being green – was more important than price or range confidence for electric vehicle consumers.

“High purchase costs and short driving ranges have been considered to be the main factors which impede people’s decision to buy electric vehicles,” he said.

“Since electricity needs to be produced from renewable energy sources for electric vehicles to be a true green alternative, the environmental performance has also been presumed to be a factor.”unplugged-performance-tesla-model-s-02-668x409

In a newly published study titled Consumer purchase intentions for electric vehicles: Is green more important than price and range? Dr Degirmenci found environmental performance was in fact an even stronger predictor of purchase intention over price and range confidence.

The study involved interviews with 40 consumers and a survey with 167 people who participated in test drives with plug-in battery electric vehicles in Germany.

“We found the majority of participants placed great emphasis on the need for electricity for electric vehicles to be produced from renewable energy sources in order for them to be a true alternative,” he said.

Dr Degirmenci said when considering greenhouse gas emissions it was important to acknowledge the difference between on-road emissions only taking into account the fuel used, and well-to-wheel emissions including all emissions related to fuel production, processing, distribution and use.

“For example, a petrol-driven vehicle produces 119g CO2-e/km, of which most are on-road emissions. In comparison, an electric vehicle produces zero on-road emissions,” he said.

“However, if electricity is generated from coal to charge an electric vehicle it produces 139g CO2-e/km well-to-wheel emissions, compared with only 9g CO2-e/km well-to-wheel emissions with electricity from renewable energy sources.”

Dr Degirmenci said the results of the study were relevant to Australia because the transport sector accounted for 16 per cent of the country’s greenhouse gas emissions and 85 per cent of these were generated by road transport.

“In this regard, a transition from conventional combustion vehicles to electric vehicles has the potential to reduce Australia’s greenhouse gas emissions substantially, if that electricity is produced from renewable energy sources,” Dr Degirmenci said.


Researchers succeed in producing OLED electrodes from graphene

Orange luminous OLED on a graphene electrode. The two-euro coin serves as a comparison of sizes. (Image: Fraunhofer FEP)

Researchers succeed in producing OLED electrodes from graphene

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP from Dresden, together with partners, has succeeded for the first time in producing OLED electrodes from graphene. The electrodes have an area of 2 × 1 square centimeters.

“This was a real breakthrough in research and integration of extremely demanding materials,” says FEP’s project leader Dr. Beatrice Beyer. The process was developed and optimized in the EU-funded project “Gladiator” (Graphene Layers: Production, Characterization and Integration) together with partners from industry and research.

Orange luminous OLED on a graphene electrode. The two-euro coin serves as a comparison of sizes. (Image: Fraunhofer FEP)

Graphene is considered a new miracle material. The advantages of the carbon compound are impressive: graphene is light, transparent and extremely hard and has more tensile strength than steel.

Moreover, it is flexible and extremely conductive for heat or electricity. Graphene consists of a single layer of carbon atoms which are assembled in a kind of honeycomb pattern. It is only 0.3 nanometers thick, which is about one hundred thousandth of a human hair. Graphene has a variety of applications – for example, as a touchscreen in smartphones.

Chemical reaction of copper, methane and hydrogen

The production of the OLED electrodes takes place in a vacuum. In a steel chamber, a wafer plate of high-purity copper is heated to about 800 degrees. The research team then supplies a mixture of methane and hydrogen and initiates a chemical reaction. The methane dissolves in the copper and forms carbon atoms, which spread on the surface. This process only takes a few minutes. After a cooling phase, a carrier polymer is placed on the graphene and the copper plate is etched away.

Gladiator project was launched in November 2013. The Fraunhofer team is working on the next steps until the conclusion in April 2017. During the remainder of the project, impurities and defects which occur during the transfer of the wafer-thin graphene to another carrier material are to be minimized.

The project is supported by the EU Commission with a total of 12.4 million euros. The Fraunhofer Institute’s important industrial partners are the Spanish company Graphenea S.A., which is responsible for the production of the graphene electrodes, as well as the British Aixtron Ltd., which is responsible for the construction of the production CVD reactors.

Applications from photovoltaics to medicine

“The first products could already be launched in two to three years”, says Beyer with confidence.

Due to their flexibility, the graphene electrodes are ideal for touch screens. They do not break when the device drops to the ground. Instead of glass, one would use a transparent polymer film. 
Many other applications are also conceivable: in windows, the transparent graphene could regulate the light transmission or serve as an electrode in polarization filters.

Graphene can also be used in photovoltaics, high-tech textiles and even in medicine.

Source: Fraunhofer Institute for Electron Beam and Plasma Technology FEP

New silver metamaterial will help create an invisibility cloak and expedite computer processing

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An example of a metasurface, which can create negative refraction. (Image: Birck Nanotechnology Center, Purdue University)

Posted: Dec 28, 2015
A team of scientists from the Moscow Institute of Physics and Technology (MIPT) and the Landau Institute for Theoretical Physics in the Russian Academy of Sciences has proposed a two-dimensional metamaterial composed of silver elements, that refracts light in an unusual way.

The research has been published on November 18 in Optical Material Express (“Negative-angle refraction and reflection of visible light with a planar array of silver dimers”). In the future, these structures will be able to be used to develop compact optical devices, as well as to create an “invisibility cloak.”

The results of computer simulations carried out by the authors showed that it would be a high performance material for light with a wavelength from 400-500nm (violet, blue and light blue). Efficiency in this case is defined as the percentage of light scattered in a desired direction. The efficiency of the material is approximately 70% for refraction, and 80% for reflection of the light.

Theoretically, the efficiency could reach 100%, but in real metals there are losses due to ohm resistance.

A metamaterial is a material, the properties of which are created by an artificial periodic structure. The prefix “meta” indicates that the characteristics of the material are beyond what we see in nature. Most often, when we talk about metamaterials, we mean materials with a negative refractive index.

When light is incident on the surface of such a material, the refracted light is on the same side of the normal to the surface as the incident light. The difference between the behaviour of the light in a medium with a positive and a negative refractive index can be seen, for example, when a rod is immersed in liquid.

The existence of substances with a negative refractive index was predicted as early as the middle of the 20th century. In 1976 Soviet physicist V.G. Veselago published an article that theoretically describes their properties, including an unusual refraction of light. The term “metamaterials” for such substances was suggested by Roger Walser in 1999. The first samples of metamaterials were made from arrays of thin wires and only worked with microwave radiation.

Importantly, the unusual optical effects do not necessarily imply the use of the volumetric (3d) metamaterials. You can also manipulate the light with the help of two-dimensional structures – so-called metasurfaces. In fact, it is a thin film composed of individual elements.

An example of a metasurface, which can create negative refraction

An example of a metasurface, which can create negative refraction. (Image: Birck Nanotechnology Center, Purdue University)

The principle of operation of the metasurface is based on the phenomenon of diffraction. Any flat periodic array can be viewed as a diffraction lattice, which splits the incident light into a few rays. The number and direction of the rays depends on geometrical parameters: the angle of incidence, wavelength and the period of the lattice. The structure of the unit cell, in turn, determines how the energy of the incident light is distributed between the rays. For a negative refractive index it is necessary that all but one of the diffraction rays are suppressed, then all of the incident light will be directed in the required direction.

This idea underlies the recent work by the group of scientists from the Moscow Institute of Physics and Technology and the Landau Institute for Theoretical Physics. The unit cell of the proposed lattice is composed of a pair of closely spaced silver cylinders with a radius of the order of 100 nanometres (see figure). Such a structure is simple and operates at optical wavelengths, while most analogues have more complex geometries and only work with microwaves.

The effective interaction of pairs of metal cylinders with light is due to the plasmon resonance effect. Light is absorbed by the metal rods, forcing the electrons in the metal to oscillate and re-radiate. Researchers were able to adjust the parameters of the cell so that the resulting optical lattice response is consistent with abnormal (i.e. negative) refraction of the incident wave (see figure). Interestingly, by reversing the orientation of the cylinder pairs you can get an abnormal reflection effect. It should be noted that the scheme works with a wide range of angles of incidence.

Abnormal refraction of light on a metamaterial

Variants of the proposed structure for the pair of silver cylinders. (Image courtesy of the authors of the study)

The results achieved can be applied to control optical signals in ultra-compact devices. In this case we are talking primarily about optical transmission and information processing technologies, which will help expedite computer processing in the future. The conventional electrical interconnects used in modern chips are operating at the limit of their carrying capacities and inhibit further growth in computing performance.To replace the electrical interconnects by optical we need to be able to effectively control optical signals at nanoscale. In order to solve this problem the efforts of the scientific community are focused to a large extent on creating structures capable of “turning” the light in the desired direction.

It should be noted that an experimental demonstration of anomalous scattering using the lattice described above requires the manufacture of smooth metal cylinders separated by a very small distance (less than 10 nanometres). This is quite a difficult practical problem, the solution of which could be a breakthrough for modern photonics.

Source: Moscow Institute of Physics and Technology