Tag Archives: solar power

Perovskite Could Convert Up To 44% Of Light Into Electricity

Perovskites are a family of crystals that show promising properties for applications in nano-technology. However, one useful property that until now was unobserved in perovskites is so-called carrier multiplication – an effect that makes materials much more efficient in converting light into electricity. New research, led by   (UvA-IoP) physicists Dr Chris de Weerd and Dr Leyre Gomez from the group of Prof. Tom Gregorkiewicz, has now shown that certain perovskites in fact do have this desirable propertyCrystals are configurations of atoms, molecules or ions, that are ordered in a structure that repeats itself in all directions. We have all encountered some crystals in everyday life: ordinary salt, diamond and even snowflakes are examples. What is perhaps less well-known is that certain crystals show very interesting properties when their size is not that of our everyday life but that of nanometers – a few billionths of a meter.

Perovskites – named after 19th century Russian mineralogist Lev Perovski – form a particular family of materials that all share the same crystal structure. These perovskites have many desirable electronic properties, making them useful for constructing for example LEDs, TV-screens, solar cells and lasers. A property which so far had not been shown to exist in perovskites is carrier multiplication. When semiconductors – in solar cells, for example – convert the energy of light into electricity, this is usually done one particle at a time: a single infalling photon results in a single excited electron (and the corresponding ‘hole’ where the electron used to be) that can carry an electrical current. However, in certain materials, if the infalling light is energetic enough, further electron-hole pairs can be excited as a result; it is this process that is known as carrier multiplication.

Until now, carrier multiplication had not been reported for perovskites. That we have now found it is of great fundamental impact on this upcoming material. For example, this shows that perovskite nanocrystals can be used to construct very efficient photodetectors, and in the future perhaps solar cells”, says De Weerd, who successfully defended her PhD thesis based on this and other research last week.

When carrier multiplication occurs, the conversion from light into electricity can become much more efficient. For example, in ordinary solar cells there is a theoretical limit (the so-called Shockley-Queisser limit) on the amount of energy that can be converted in this way: at most a little over 33% of the solar power gets turned into electrical power. In semiconductor nanocrystals that feature the carrier multiplication effect, however, a maximum efficiency of up to 44% is predicted.

The paper in which the researchers report on their findings was published in Nature Communications this week.

Source: http://iop.uva.nl/

Solar Powered Car

The Sion is the first electric car capable of recharging its batteries from the sun. From now on, you’ll have to worry about range a little less. For only 16.000 € excluding the battery (4000 euros or to rent). With the dynamic integration of solar cells in the body work, we set new measures on the road while convincing with an exceptional design concept. The full efficiency of the Sion is guaranteed by the lightweight design. The exterior is mainly made up of rust-proof polycarbonate. It further is scratch-resistant. The most unique feature in the body work are the solar cells, which are located on the roof, on both sides as on the hood and the rear.

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The cockpit  uses a very simple design, showing you how fast you are going and the charging level of your battery. On the left side you can see the number of kilometers generated through the viSono System. After 24 hours, these kilometers will be transferred to the right side, where they are added to the total range left. The Sion copes with the requirements of your daily life: A range of 250km, high power rapid charging, and a sophisticated interior concept with an optional trailer hitch.
The Sion is equipped with 330 integrated solar cells, which recharge the battery through the power of the sun. To protect them from harmful environmental influences the solar cells are covered with polycarbonate. It is shatterproof, light and particularly weather resistant. Under proper conditions the solar cells generate enough energy, to cover 30 kilometers per day with the Sion. This system is called  viSono. Thanks to the technology of bidirectional charging the Sion can not only generate but also provide energy. This feature turns the car into a mobile power station. Using a household plug, all common electronic devices with up to 2,7kW can be powered by the Sion. You can plug in your electronic devices and power them with the Sions battery. Over a type 2 plug the Sion can provide even more power with up to 7,6 kW.
For air filtering  a  special moss is integrated into the dashboard. It filters up to twenty percent of the fine dust particles and has a regulating effect on the humidity inside the Sion. No worries, you do not have to water it. It requires no special care at all.

Electric Car: How To Make Super-Fast Charging Batteries

Researchers have identified a group of materials that could be used to make even higher power batteries. The researchers, from the University of Cambridge, used materials with a complex crystalline structure and found that lithium ions move through them at rates that far exceed those of typical electrode materials, which equates to a much faster-charging battery. Although these materials, known as niobium tungsten oxides, do not result in higher energy densities when used under typical cycling rates, they come into their own for fast charging applications. Additionally, their physical structure and chemical behaviour give researchers a valuable insight into how a safe, super-fast charging battery could be constructed, and suggest that the solution to next-generation batteries may come from unconventional materials.

Many of the technologies we use every day have been getting smaller, faster and cheaper each year – with the notable exception of batteries. Apart from the possibility of a smartphone which could be fully charged in minutes, the challenges associated with making a better battery are holding back the widespread adoption of two major clean technologies: electric cars and grid-scale storage for solar power.

We’re always looking for materials with high-rate battery performance, which would result in a much faster charge and could also deliver high power output,” said Dr Kent Griffith, a postdoctoral researcher in Cambridge’s Department of Chemistry and the paper’s first author.

In their simplest form, batteries are made of three components: a positive electrode, a negative electrode and an electrolyte. When a battery is charging, lithium ions are extracted from the positive electrode and move through the crystal structure and electrolyte to the negative electrode, where they are stored. The faster this process occurs, the faster the battery can be charged. In the search for new electrode materials, researchers normally try to make the particles smaller. “The idea is that if you make the distance the lithium ions have to travel shorter, it should give you higher rate performance,” said Griffith. “But it’s difficult to make a practical battery with nanoparticles: you get a lot more unwanted chemical reactions with the electrolyte, so the battery doesn’t last as long, plus it’s expensive to make.

Nanoparticles can be tricky to make, which is why we’re searching for materials that inherently have the properties we’re looking for even when they are used as comparatively large micron-sized particles. This means that you don’t have to go through a complicated process to make them, which keeps costs low,” explained Professor Clare Grey, also from the Department of Chemistry and the paper’s senior author. “Nanoparticles are also challenging to work with on a practical level, as they tend to be quite ‘fluffy’, so it’s difficult to pack them tightly together, which is key for a battery’s volumetric energy density.”

The results are reported in the journal Nature.

Source: https://www.cam.ac.uk/