Scientists have discovered a new and strange kind of photovoltaic effect

Scientists at the University of Warwick have reported that they have discovered a completely new type of photovoltaic effect called “flexo-photovoltaics.” To create this effect, you need to take an ordinary silicon crystal and hit the surface of this material with something unusually hard and sharp. Further studies of this kind of effect will open the way to the creation of a new method of energy conversion, which can form the basis, for example, of highly efficient solar cells.

Modern solar cells, as a rule, are made of silicon, inside of which there are many semiconductor p-n junctions that create an uneven electric field in the material. Each such transition, which is the boundary of regions filled with carriers of negative electric charge (electrons) and positive charge (electron holes), absorbs a photon of light, a pair is formed – an electron and a hole, which creates an electric potential. Such solar cells have one drawback – their maximum efficiency is limited by the laws of physics, it cannot exceed 33.7 percent.

But the new photovoltaic effect has no such limitations. The only limitation in this case is that a new effect appears only in the case of using materials that do not have the so-called central symmetry of their structure.

In their work, the researchers used “brute force”, they took and with a sufficiently large force hit the tip of the atomic force microscope on the surface of the crystal. The resulting mechanical stress was so great that it broke the central symmetry of the crystal structure, and new photovoltaic effects began to appear on its surface. This approach worked for crystals of different types: strontium titanate, titanium oxide and silicon. “The new photovoltaic effect does not have any thermodynamic limits due to the fact that it is not based on the use of a semiconductor p-n junction,” the researchers write.

It is still too early to talk about the value that solar panels will have based on the new effect. An approximate answer to this question can only be given by further experiments and research in this direction. In addition, there are a lot of questions from the side of practical implementation.

“We see something like a matrix of microscopic thorns pressing on the surface of an element of a conventional solar cell,” the researchers write, “This is the simplest and most understandable way, but it can hardly be classified as a cheap and reasonable solution. Another option is to create defects in the silicon structure that create the necessary mechanical stress, but then questions will arise related to the reliability and durability of such solar cells. “

And in conclusion, it should be noted that scientists are going to continue to work in this direction, studying the features of the new photovoltaic effect and, in parallel, looking for ways that are suitable for its further practical application

. Source: www.dailytechinfo.org