A Major Breakthrough in Perovskite Photovoltaic Cells: Wear a New Protective Cover to Withstand High Humidity and Heat Environments

As global sustainability and clean energy megatrends shape a greener future energy strategy for the planet, renewable technologies such as wind and solar power are key areas of focus for research. In the field of solar technology, the emerging field of perovskite solar cells (PSCs) has gained popularity over the past 15 years for offering high power conversion efficiencies (PCEs). However, in a field dominated by silicon solar cells, perovskite solar cells, a relatively new technology, must meet two other key requirements for successful commercialization: stability and scalability. In a new study, researchers from King Abdullah University of Science and Technology (KAUST) report a major milestone in the first successful photovoltaic (PV) damp heat test for PSCs. The Damp Heat Test is an accelerated and rigorous environmental aging test designed to determine the ability of solar panels to withstand high humidity penetration and long-term exposure to high temperatures. Tests were performed for 1000 hours in a controlled environment at 85% humidity and 85 degrees Celsius. It is designed to replicate years of outdoor exposure and evaluate factors such as corrosion and delamination. The rigor of the tests is in line with commercialization requirements that PV technology must provide a 25- to 30-year warranty for conventional crystalline silicon modules. To pass the test, the solar cell must retain 95% of its initial performance. Perovskites are known to be very sensitive and highly affected by humidity. This fragility of 3D perovskite films allows unwanted penetration of atmospheric media, such as moisture, with limited elasticity to heat. Stability is critical to their operation. KAUST researchers found that the introduction of a 2D perovskite passivation layer can block moisture while improving power conversion efficiency and PSC lifetime. Can it replace silicon? The particularity of perovskite is that it is a thin-film technology. As with conventional solar cells, two contacts made of a specific type of material are still required. One collects electrons and the other collects positively charged "holes". Unlike silicon wafers, perovskite inks can be directly coated on glass substrates, combined with anti-solvent extraction, and then thermally annealed to fully crystallize the perovskite films. Perovskite inks are basically formulated from salt mixtures in polar aprotic solvents at low temperatures (usually below 100 Celcius). A significant advantage of perovskite photovoltaics is that precursor materials can be prepared without the need for expensive equipment and energy-intensive environments exceeding 1,000 degrees, which is typical for more traditional semiconductors such as silicon. "This is a very simple way to make solar cells, and while the optoelectronic properties are not unique, they are excellent," the researchers said. "They are comparable to very high-quality conventional semiconductors. This is remarkable," they added. , by changing the composition, it is also possible to adjust the spectral sensitivity of the entire solar spectrum from ultraviolet to infrared. This is very attractive for some applications. After performance and stability, the remaining challenge is scalability. Most solar cell applications are concentrated in utility-scale sectors and roof panels. "This market is silicon-based, and it will be silicon-based for at least the next 20 years," the researchers said. "Our main focus now is to improve the performance of perovskite solar cells to advance more efficient 'tandem' solutions," said the researchers. pairing conventional silicon and perovskite. The current findings will greatly contribute to improving the reliability of perovskite-silicon tandem solar cells."