the effort to eradicate it is already bearing fruit

Perovskites are one of the best assets of photovoltaic technologies. We don’t say it; It is defended by Ignacio Mártil de la Plaza, PhD in Physics and Professor of Electronics at the Complutense University of Madrid. This expert in advanced solar cell technologies explained to us during the conversation we had with him at the beginning of 2021 that perovskites have traveled in ten years the same path that silicon took fifty years to travel.

The term perovskite is a generic denomination that identifies a family of materials whose crystalline structure is similar to that of a material called calcium titanate. However, the most important thing is that their attractiveness comes from properties that make them optimal from a theoretical point of view for converting solar energy into electrical energy. In addition to their high efficiency, perovskites stand out because it is possible to manufacture them with materials that are very abundant in the earth’s crust, such as carbon, nitrogen or hydrogen.

However, it is not all good news. And it is that currently the ones that work best are those that contain lead, and it is a very polluting chemical element. In fact, in some European countries, such as Switzerland, they have banned them. In recent years, much research has been done to replace lead with another similar element, and tin seemed a good candidate. The problem is that the solar cells that contain it are not as good as those made of lead because they have a much lower efficiency. Fortunately, this landscape seems to be about to change.

Lead-free perovskites with an efficiency of 24.1% are already on the horizon

Since perovskites came to the fore in the field of photovoltaic technologies, many research groups spread all over the planet have gotten to work with the aim of developing their technology and making this type of solar panel commercially viable. The first promising results came a long time ago, but few are as exciting as those achieved by a research team from Nanyang Technological University and the Agency for Science, two scientific institutions in Singapore.

These researchers have published a very interesting article in the scientific journal Nature Energy in which they explain in detail that they have succeeded in producing solar cells with lead-free perovskites and with an efficiency of 24.1%. It is not but not bad as a starting point. In isolated union the perovskites until now had reached an approximate efficiency of 25.5%, and in tandem with silicon of 29.5%. These are two competitive values, but what makes the research of these Singapore scientists so attractive is precisely that their solar cells do not contain lead. This is what makes the difference on paper.

The strategy that has allowed them to obtain this result is ingenious. Very broadly, what they have done has been to replace lead with a compound that contains zinc and ammonium, among other substances, and which, according to their tests, is more effective than the materials with which they had worked up to now. The challenge now lies in finding a way to scale this technology so that it can be used to produce solar cells for commercial applications.

This project and other similar ones that are being developed in other countries look good, and one of them will probably come to fruition. Let’s cross our fingers that this is the case. The technologies of the next generation of solar panels are at stake. In any case, there is something that is beyond doubt: perovskites are currently the best asset of photovoltaic technologiesand all the effort that is being made to make them commercially viable is worth it.

Cover image: Kindel Media

More information: Nature Energy

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