Domestic researchers have created a flexible yet efficient solar cell. Kim Gi-hwan from the Korea Institute of Energy Research noted that he, along with Professors Lee Tae-kyung from Gyeongsang National University and Kim Hae-jin from Yonsei University, successfully developed a lightweight, flexible, high-efficiency solar cell on the 3rd. The results of this research were published in the international journal 'Joule.'
Most existing solar cells are based on silicon. However, while this method is widely used due to its low production costs and ease of mass production, there are limitations to its power generation efficiency. To address this, a method known as 'tandem solar cells,' which incorporates a new material called 'perovskite' on top of the existing silicon, is gaining attention. Notably, the 'perovskite·CIGS thin-film tandem solar cell' is lightweight and flexible, allowing it to be attached to curved buildings, vehicles, and satellites, but its low efficiency and complex manufacturing process have made commercialization challenging.
The research team introduced a new method called lift-off to solve this issue. This approach involves laying a flexible polymer layer, such as polyimide, on a rigid glass substrate, creating the cell on top, and then peeling it off like a film. This method is more stable than the previous approach of manufacturing the cell directly on a flexible film and has the advantage of reducing production errors.
Additionally, the research team also resolved the issue of 'potassium diffusion,' which was one of the causes of performance degradation in the cells. When potassium from the glass substrate seeps in too much during solar cell production, it disrupts the flow of charge and decreases performance. The research team predicted that the polyimide layer could prevent potassium diffusion using simulations and successfully applied this in their experiments to avoid performance decline.
The solar cell produced through this method demonstrated a power generation efficiency of 23.64%. This significantly exceeds the previous highest efficiency of 18.1% for flexible perovskite·CIGS tandem solar cells. Moreover, in tests involving 100,000 bends, it maintained 97.7% of its original performance, proving its reliability for long-term use.
Kim Gi-hwan, the lead researcher, said, "This cell has about 10 times the power generation capacity relative to its weight compared to existing cells, and it is expected to be applicable in various fields, including building exteriors, vehicles, and aerospace, where ultra-lightweight modules are necessary." He added, "We will promote the development of processes that can be applied to a larger area and research to improve stability, greatly contributing to strengthening the competitiveness of related industries and expanding the dissemination of new and renewable energy."
References
Joule (2025), DOI : https://doi.org/10.1016/j.joule.2024.11.011