Tuesday, June 10, 2025
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Most solar panels are made of silicon, capable of transforming between 17 and 19% of solar light into usable energy. Now, this semiconductor has competition, and it is called perovskite, a mineral that has caused quite a buzz in the laboratory to revolutionize solar power generation at a lower cost
Photo by EFE Sherwin
Spain's capacity to produce solar energy, a safe and efficient renewable source, is well known. Whether in large photovoltaic parks which can reach 50,000 hectares in Spain or for domestic use, solar panels are an element that we are becoming increasingly familiar with. The conventional solar cells that make up these panels are mainly made of silicon, which is capable of transforming between 17 and 19% of the sunlight it captures into usable energy, an indicator that measures its level of efficiency. After years of development, it is now possible to find high-efficiency solar panels that reach between 20 and 23% photovoltaic conversion.
But how do the sun's rays turn into electricity? When sunlight hits a panel, the photovoltaic cells absorb light particles—known as photons—and release electrons in a process that generates an electrical current, which is then transformed into electricity. That is why the scientific community is researching new solutions to increase photovoltaic conversion levels in order to meet the challenge of obtaining more useful energy from the same surface area. And, in that race, perovskite solar cells (PSC) are at the forefront.
Efficiency, flexibility and price
This new material, discovered in 2009, is a type of solar cell made from a mineral composed of calcium oxide and titanium, the application of which is attempting to break the Shockley-Queisser theoretical limit, set at 33.7% for conventional solar cells. According to the Solar Energy Institute of the Polytechnic University of Madrid, the technological development of PSCs in the laboratory has gone from “2.8% to 27.7% photovoltaic conversion” in just 15 years, surpassing “the efficiency limits of the best silicon solar cells.”
This success is exemplified by the University of Oxford. A scientific team from the Physics Department at the prestigious British university developed a new ultra-thin material last year—up to 150 times thinner than a silicon wafer—based on the multi-junction approach. This new material achieved an energy efficiency of over 27%, certified by the National Institute of Advanced Industrial Science and Technology of Japan (AIST).
“We believe that, over time, this approach could allow photovoltaic devices to achieve efficiencies above 45%,” predicted postdoctoral researcher in Physics at the University of Oxford, Shuaifeng Hu, after the publication of the study conducted in the laboratory.
Based on a synthetic material that can be produced at a low cost, their price is another advantage of these solar cells compared to silicon, which is much more difficult to extract. And as they are a thin, more flexible and lightweight film, they could cover almost any surface: from vehicle roofs to buildings, windows or even mobile phones.
Tandem cells: from alternative to complementary
As explained above, silicon solar cells convert around 20% of solar energy, or, if understood in reverse, it could be said that they waste 80% of solar light, while perovskite solar cells capture a wider spectrum of light in a single cell.
Combining the potential of both components results in tandem cells, where perovskite is placed at the top of the cell to absorb high energy light with shorter wave lengths, while crystalline silicon is placed below to capture low energy light from longer waves. Instead of being seen as alternatives, when working together these cells allow, in the eyes of experts, to surpass the theoretical efficiency limit of a single solar cell.
The current record for efficiency was set by Longi, a Chinese solar technology company, with a conversion of 34.85%, certified by the US National Renewable Energy Laboratory (NREL), surpassing its own previous record of 34.6% from June 2024.
Durability, its “kryptonite”
Scaling up the production of this laboratory technology to the commercial phase is the next challenge. Despite their multiple advantages, perovskite cells are currently limited by their durability, as they degrade more quickly when continuously exposed to the sun. Paradoxically, the light they convert into electricity is, at the same time, their biggest obstacle.
In this regard, the FQM-204 Group from the University of Córdoba, with the participation of the Georgia Institute of Technology, has managed to maintain the performance of the photovoltaic cell after one thousand hours of sun exposure thanks to a “geometric adjustment” in a laboratory-scale test. This advance confirms this alternative to traditional panels, laying the foundations for the new solar energy paradigm.
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