How to solve the performance degradation problem of perovskite solar cells?

Perovskite solar cells hold promise for improved photoelectric conversion efficiency, but they suffer from one of the biggest drawbacks—their performance degrades over time when exposed to sunlight. A team of scientists from the United States, China and South Korea wrote in the latest issue of "Nature" that they had performed a simple treatment on the surface of perovskite solar cells, solved the problem of degradation, and cleared the way for the application of thin-film solar cell technology. the biggest obstacle.

Perovskites are a group of materials that have the same atomic arrangement (crystal structure) as the mineral perovskite oxides. Metal halide perovskites, one of the "family members", are prepared for their great application potential in the field of high-efficiency and energy-saving thin-film solar cells. attention. Perovskite solar cells are much cheaper to manufacture than silicon-based solar cells, but they have one of the biggest drawbacks – their performance degrades when exposed to light for a long time. If this problem can be properly addressed, it will help solar technology. "Fly into the homes of ordinary people".

Yang Yang, the head of the latest research and a professor of materials science and engineering at the University of California, Los Angeles, explained that for solar cell defects, the common treatment method currently used by scientists is to deposit a layer of organic ions on the surface to make the surface negatively charged. While this treatment was designed to improve the energy-conversion efficiency of perovskite solar cells, it also allowed too many electrons to accumulate on the cell's surface. This destabilizes the orderly arrangement of atoms, making perovskite solar cells less and less efficient over time, ultimately rendering them uncommercial.

In light of this discovery, the team found a way to address the degradation of the battery by pairing positively charged ions with negatively charged ions on the surface, which made the surface electrons more neutral and stable.

The team tested the durability of the treated solar cells under conditions that accelerate cell aging and under conditions that simulate all-weather sunlight. The results showed that the cells maintained 87 percent of their initial photoelectric conversion efficiency for more than 2,000 hours. In contrast, under the same conditions and for the same amount of time, the performance of the untreated solar cells dropped to 65 percent .

"Our perovskite solar cells are among the most stable in efficiency reported to date, and our latest research lays the groundwork for the commercialization and widespread adoption of perovskite solar cell technology," said the researchers. On the basis of further developing and perfecting this technology, we can design more stable perovskite solar cells."