A team of researchers from the Martin Luther University (MLU), in Germany, has developed a new method based on ferroelectric crystals that can open the door to more durable and much more efficient solar panels.
Most of the photoelectric cells that make up commercial solar panels are made from silicon. This material has been used for a long time because it is cheap and relatively efficient, although not very efficient. In addition, several researchers they have already alerted that this type of silicon-based cells is reaching its limit and new materials must be sought.
Among the possible substitutes that the scientific community is studying are some ferroelectric crystals such as barium titanate or mixed barium titanium oxide. These materials have long attracted a lot of interest due to the high voltage that they are able to achieve.
“Ferroelectric means that the material has spatially separated positive and negative charges,” he explains. Akash Bhatnagar, MLU investigator and lead author of the study. “The separation of charges gives rise to an asymmetric structure that allows electricity to be generated from light.”
German scientists have been working with these materials for some time and have published their results in the journal Scientific advances. In their study they show that by placing alternately layers of barium titanate, strontium titanate and calcium titanate crystals, it is achieved greatly increase the efficiency of solar panels.
A thousand times more efficient mix of components
The researchers found that pure barium titanate absorbs very little light and generates little electrical current. Which led them to experiment with different combinations of materials.
The team observed that the photovoltaic effect increases considerably if the ferroelectric layer alternates not only with one, but with two layers paraelectric different. “We embedded the barium titanate between the strontium titanate and the calcium titanate,” explains Yeseul Yun, another of the study’s authors. “So we were able to obtain a material with 500 layers of about 200 nanometers (0.0002 mm) thick.”
In measurements carried out by the researchers they observed that the current flow with this arrangement of materials was 1,000 times stronger than using pure barium titanate of a similar thickness. These results surprised even the scientists who in their tests had reduced to almost two-thirds the amount of barium titanate as the main photoelectric component of the new combination.
Also, they discovered that this new mix of materials results in some very robust photoelectric cells They can maintain the same level of efficiency for more than six months.
Researchers are still finding out why this impressive electrical flux occurs in this material. Although they are clear that The potential demonstrated by this method can be applied to a new type of solar panel. “The layered structure shows higher performance in all temperature ranges than pure ferroelectrics. In addition, the crystals are much more durable and do not require special packaging,” says Bhatnagar.
Apart from the forroelectric crystals, another material that has revolutionized the scientific community is the perovskite. “I would say that perovskites are one of the most interesting opportunities for solar cells in the immediate future,” he tells NBC. David Mitzi, Professor of Mechanical Engineering and Materials Science at Duke University.
This material can collect solar energy on its own or together with conventional silicon cells, increasing its efficiency from 29% to 40% or even above 50% according to some studies. Perovskite It is a mineral that is being studied a lot and that for now offers an energy efficiency similar to silicon, although it offers many more advantages. Among other things, making solar panels from perovskite is easier than with silicon cells. In addition, it can produce panels as thin as sheets of paper, or it can even be used to make solar panels. totally transparent. This would allow to implement them in windows, in the chassis of cars and other means of transport or even in textile materials that generate energy.
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