Perovskite cells: a scientific revolution in the field of solar energy
Perovskite cells: a scientific revolution in the field of solar energy
Solar energy is considered one of the most important sources ofrenewable energy, which plays a prominent role in achieving environmental sustainability and meeting the increasing clean energy needs of modern societies. Solar energy generation exploits the sunlight that reaches the Earth every day, and this energy is converted into electricity that can be used in various residential, commercial and industrial sectors.
Solar cells or solar panels are mainly composed of semiconductors, specifically silicon, as sunlight is absorbed by these cells. To convert it into an electric current. Solar cells are known for being one of the most promising solutions for achieving the energy transition, that is, the gradual transition away from fossil fuels. Therefore, over decades, solar energy has witnessed technological developments to reduce the cost of its production and increase its efficiency.
Thanks to the improvement of technology and the decline in manufacturing costs, solar cells have become more abundant, and this is in parallel with the scientific community’s continuous efforts to develop and improve solar cells, by inventing and experimenting with new materials that can outperform silicon, such as perovskite.
What is perovskite?
Perovskite is a semiconductor material - its molecular formula is CaTiO3 - that was first found in the Ural Mountains in Russia in 1839, and was named after the Russian metallurgist Lev Perovsky. This material is characterized by a special crystalline structure, which enabled materials scientists to prove its photovoltaic capabilities in 2009.
Since then, many research groups have developed perovskite, in preparation for relying on it instead of silicon in solar cells. This is because the material has shown a higher ability than silicon in converting parts of the light spectrum into electricity, and it can also be used in an integrated manner - along with silicon - in solar cells. To raise efficiency.
In this context, engineers from the University of Colorado Boulder discovered a new way to manufacture perovskite solar cells. This new method of producing perovskite cells could lead to a revolution in the solar energy sector, by reducing the cost of building and operating systems, and raising the efficiency of their work to suit many applications, such as electric cars and home lighting.
This new method of manufacturing perovskite solar cells has been received with a great deal of welcome by the scientific community. Because it could bring about a qualitative shift in this promising sector. These efforts come within the efforts of various scholars and institutions around the world. To develop new types of solar cells that can operate more efficiently, compared to the solar panels used today.
The new generation of solar cells
In a new research published on February 26 of this year in the journal Nature Energy, a researcher from the University of Colorado Bold and his collaborators revealed an innovative method for manufacturing perovskite solar cells, which the scientific community considered a very important achievement to begin manufacturing the next generation of solar energy technology.
To understand the current landscape in the solar energy sector, almost all solar panels are made of silicon, which has an efficiency of up to 22%. This means that silicon panels can only convert about a fifth of the sun's energy that falls on them into electricity; Because silicon absorbs a limited percentage of the wavelengths of sunlight.
This relatively low efficiency of traditional silicon solar panels - combined with the high cost of producing these panels - has opened the door to experimenting with many other alternatives. One of the most prominent of these alternatives is perovskite. Perovskite is a synthetic semiconductor material, capable of converting solar energy into electricity more efficiently than silicon, and at a lower production cost.
In this context, Michael McGee, professor in the Department of Chemical and Biological Engineering, and fellow of the Institute for Renewable and Sustainable Energy at the University of Colorado Boulder, said: “Perovskite will radically change the rules of solar panel manufacturing.”
Scientists are testing perovskite solar cells by placing them on top of traditional silicon cells to make composite cells. Using the two materials can increase the efficiency of panels by more than 50%, as each absorbs a different part of the sun’s spectrum.
McGhee said: “In light of the rapid transformation of many sectors - most notably the transportation sector - to rely on electricity instead of other energy sources - we hope that this new way of working solar cells will reduce dependence on fossil fuels in producing electricity; So that we can eventually get rid of coal-fired power plants or even natural gas. If we want the future to be sustainable and completely dependent on renewable energy, we must now expand the markets for wind and solar energy by at least five to ten times what they are today.”
The problem of manufacturing perovskite cells
The main challenge in manufacturing perovskite solar panels on a commercial scale is the process of coating this semiconducting material on glass panels, which form the basic building blocks of solar cells. Currently, the aforementioned coating process is carried out on a laboratory scale in a small box filled with an inactive gas such as nitrogen. To prevent perovskite from interacting with oxygen, because air can cause the efficiency of perovskite to decrease. However, when trying to apply the previous process on a larger industrial scale, the matter becomes more complicated.
From here, McGee and his collaborators set out to find a new way to coat perovskite on glass panels in a way that prevents the material from interacting with air. They found that adding the compound dimethylammonium formate “DMAFo” to the perovskite solution before coating could prevent the oxidation process.
This discovery allows the coating of semiconductor materials to be performed without restrictions on the nature of the surrounding air, facilitating the transfer of this application to industry. In addition to the above, experiments have shown that perovskite cells made using DMAFo alone can achieve an efficiency of approximately 25%, and the additive also improves the stability of the cells.
Another aspect that should be discussed is the lifespan of solar panels. Silicone panels can usually maintain at least 80% of their performance after 25 years of use, losing about 1% of their efficiency annually. On the other hand, we find perovskite cells with a shorter lifespan, as they decompose faster in the air, but the new method of producing these cells using “DMAFo” retained 90% of their performance after the researchers exposed them to LED light that simulates sunlight for 700 hours. In contrast, cells made in air without using DMAFo degraded rapidly after only 300 hours.
Encouraging results, but we need more
The previous results are very encouraging, but we must not forget that there are more than 8,000 hours in one year; Therefore, longer tests are needed; To determine how well these new cells can withstand the additional work, it would be too early to say that perovskite cells have the same stability as silicon sheets. However, it is enough to know that we are on the right path towards developing solar cells.
The new study brings perovskite solar cells one step closer to commercial use. At the same time, the McGhee team is actively working to develop composite cells with an actual efficiency of more than 30%, and with the same operating life as silicon panels.
McGee also leads an industrial-academic partnership in cooperation with researchers from three other universities and two companies, a partnership that was able to obtain funding worth $9 million from the US Department of Energy last year; To develop stable composite perovskite cells; So that it can actually be used commercially.
With higher efficiency and lower prices, these composite cells could have broader applications than current silicon panels, including installation on the roofs of electric cars, and powering drones and sailboats.
What is interesting here is that, after a decade of research into perovskites, engineers have been able to build solar cells that are as efficient as silicon cells, which were invented and developed over the past seventy years. This means that the space available for developing perovskite cells is still large, as this new technology is expected to dominate the solar panel marketin the future.
