A collaborative study by the Department of Electronic Engineering at CUHK has found that ion-induced field screening is a dominant factor in the operational stability of perovskite solar cells. The findings will help lay the foundation for new strategies to improve the lifetime of the next-generation solar cells.
The solar cell market is currently dominated by traditional silicon-based technologies, which account for 95 percent of the market. On the other hand, perovskite solar cells are found to offer better performance and lower manufacturing costs. However, perovskite solar cells can only last a few years, which lags silicon cells by roughly one order of magnitude (ten times less) in a guaranteed lifetime, which is a major technical obstacle in its commercialization.
A recent study by CUHK found that the long-term operation of the equipment is not the decisive factor in battery degradation. Instead, ion-induced field screening is the cause of the degradation in perovskite solar cells. When the perovskite semiconductor is exposed to external stressors, such as exposure to sunlight, the mobile ions generated will shield the built-in electric field in the perovskite, thereby reducing the efficiency of photogenerated charges and lowering the current generation capacity from the battery.
The findings confirm that ion-induced field screening is related to the degradation of perovskite solar cells, it is expected to extend the stability of perovskite solar cells so that their guaranteed lifespan is close to the industry standard of 25 years.
Martin Stolterfoht, VC Early Career Associate Professor at the Department of Electronic Engineering of CUHK, pointed out that the mechanism discovered this time will help speed up the development of more stable perovskite tandem batteries. For example, the battery’s service life can be accurately predicted through its detected ion characteristics, saving time and effort in stability tests that typically span weeks to months.
The findings have been published in the journal “Nature Energy.”
