Researchers at the School of Engineering at the Hong Kong University of Science and Technology (HKUST) have discovered a flaw that makes perovskite-based solar panels unstable. By solving the problem, the researchers have paved the way for the widespread introduction of high-efficiency solar panels.
On average, commercially available solar panels have an electric power conversion efficiency (EPE) of 15-20%. In other words, of all the sunlight falling on a solar panel, it can convert no more than 20% into electricity. This is under ideal conditions. In cloudy weather or in winter, the figures will be lower.
Therefore, the efficiency of solar cells needs to be improved, and perovskite can help. Thanks to the use of perovskites, solar panels can achieve energy conversion rates of up to 33%. In addition, solar panels based on perovskite are cheaper to produce and more environmentally friendly. They can also be manufactured in a variety of colors to facilitate urban installations.
Despite these advantages, perovskite has a serious problem. Sharp temperature fluctuations or prolonged exposure to moisture and oxygen make the material unstable, and the solar cell stops working. This is the main obstacle to the introduction of perovskite on a commercial scale.
The researchers, led by Zhou Yuanyuan, an associate professor at HKUST, studied the microstructure of perovskite and found that the material’s crystal grains have concavities on their surfaces. When used in solar cells, these concavities affect the structural continuity of the perovskite film and cause it to break under different conditions. In addition, researchers have found that concavity is a limiting factor in the overall energy conversion efficiency of perovskite-based solar cells. Thus, correcting the deficiency can not only improve the reliability of the panels, but can also help create more efficient solar panels.
In their study, the team found that treating the perovskite material with a surfactant molecule, specifically the potassium salt of tridecafluorohexane-1-sulfonic acid, promotes ion diffusion during the manufacture of solar panel films.
Solar cells manufactured using the treated perovskite material have demonstrated better efficiency and stability under humid and warm environments, thermal cycling, and maximum power point tracking tests.
«The structure and geometry of individual crystal grains is the source of the performance of perovskite semiconductors and solar cells,» Zhou said.
Source: interestingengineering