The numbers 29, 30 and 32 are not just random numbers; they represent the efficiency of solar cells, as measured by the proportion of incidental sunlight converted into electrical power. However, efficiency does not stop at 32 as tandem solar cell efficiency has already surpassed 32%.
Dr. Artiom Magomedov, researcher at KTU Faculty of Chemical Technology. Image Credit: Kaunas University of Technology
There is a kind of race going on among research teams around the world. In the last year, the solar cell efficiency record has been broken three or four times, it’s just the publication of scientific papers that takes time.
Dr. Artiom Magomedov, Study Co-Author and Researcher, Kaunas University of Technology
The most recent reported record for tandem perovskite solar cells is 32.5 percent, according to Dr. Magomedov, co-author of a new study published in the prominent scientific magazine Science. The study describes the advancements in silicon-perovskite tandem cells that have enabled this.
Dr. Magomedov added, “Tandem solar cells have more than ten layers, so it is technologically very challenging to ensure their smooth operation. The development of such solar cells involves a large number of researchers. For example, our research team is responsible for one of the layers, which is made of hole-transporting materials.”
In 2018, a group of KTU chemists created a substance that generates a molecule-thick layer, commonly known as a monolayer, that covers a variety of surfaces uniformly. This material has previously been used to create several highly effective solar cells. According to Dr. Magomedov, one of the invention’s developers, the KTU innovation has become standard among experts working on cutting-edge solar technology.
“Our materials are used by research groups all over the world, and you hear about their application in almost every conference presentation on the subject,” added Dr Magomedov.
The Mass Production of Next-Generation Solar Cells Will Have to Wait
Dr. Magomedov’s current scientific article is his second co-authored publication in Science, and it serves as a follow-up to the prior one, suggesting a solution to the problem at hand.
“Although our materials help achieve the highest efficiency, it is difficult to form another layer on top. After our previous paper in Science, we received a lot of attention and comments about how our materials act in different contexts. In the current paper, we show one way to address the problems,” he further stated.
More information about the KTU research team’s proposed improvement, which, along with solutions created by other scientists across the world, resulted in the building of an ultra-high-efficiency tandem solar cell, could be found in the scientific publication. A research team led by Prof Steve Albrecht of the Helmholtz-Zentrum Berlin in Germany created the ultra-high efficiency tandem solar cell.
Silicon solar cells have a peak theoretical efficiency of just 29%; due to the climate change dilemma, the world requires more and more alternative energy sources. Tandem solar cells are made up of two types of photoactive layers: silicon and a perovskite solar element.
The silicon layer gathers infrared light, while the perovskite layer collects visible blue light, boosting the efficiency of the solar cell. However, Dr Magomedov believes that it will take time for the new generation of solar cells to replace those now in use.
He noted, “In theory, electricity made by tandem solar cells would be cheaper because the additional materials used are cheaper. However, in practice, the final commercial product does not exist, and the technological processes are not ready for mass production. Moreover, the cell itself, which is only being developed in laboratories so far, also raises unanswered questions. For example, not all materials are suitable for mass production, which means that alternatives have to be found.”
According to him, one of the most difficult issues in developing these cells thus far has been their stability. Solar cells are predicted to persist for 25 years before losing 10% of their efficiency. However, due to the difficulty of testing over such a long length of time, there is no conclusive answer as to how the new generation of solar cells will wear out.
Lithuanian Chemists–World Experts in New Materials for Solar Cells
Dr. Magomedov has been interested in the synthesis and analysis of chemical materials for solar technologies since the beginning of his undergraduate studies when he joined a research group directed by KTU Professor Vytautas Getautis. As the need for novel materials for solar cells arose, chemists carved out a niche for themselves, acquiring an international reputation.
“We are probably the most specialized research group in the world,” joked Dr Magomedov.
Good outcomes, according to him, inspire people, present exciting chances for teamwork, and create new research opportunities. Being a part of an international scientific discovery is fantastic. Additionally, according to Dr. Magomedov, the advancement of solar technology is a highly current subject in the context of the modern world, and the discoveries could be used broadly.
Dr. Magomedov stated, “Broadly speaking, we are working with new electronics with a very wide range of applications. And of course, in the topic of solar technology itself, the solar energy storage and batteries issue is inevitably coming up.”
A research team of KTU chemists under the direction of Prof. Getautis is now working on a project to create a pilot manufacturing line for tandem silicon-perovskite solar cells and is exploring how to use the materials created therein in other technologies, such as light-emitting diodes. Parallel to this, basic issues like why semiconductors created in the lab function the way they do are also being investigated.
For KTU scholars, publishing in prestigious journals like “Science” or those in the “Nature” category is nothing new. Dr. Magomedov asserts that being mentioned in famous scientific journal results in both personal triumph and widespread acclaim. Participation in scientific activities on a global scale becomes considerably simpler.
Dr. Magomedov concluded, “Nowadays, when we contact partners in other countries, there is no need to lengthily introduce ourselves. People already know our work.”
Journal Reference:
Mariotti, S., et al. (2023) Interface engineering for high-performance, triple-halide perovskite–silicon tandem solar cells. Science. doi:10.1126/science.adf5872