"Remains Intact After 10,000 Folds"…Development of High-Performance 'Foldable' Solar Cell Material

Korea Research Foundation "Korea-Japan Joint Research Team Develops Transparent Conductive Film Composed of Carbon Nanotube-Polyimide"

[Asia Economy Reporter Kim Bong-su] A solar cell material that maintains high efficiency and performance even after being folded and unfolded more than 10,000 times has been developed.

On the 14th, according to the Korea Research Foundation, Professor Jeon Il (Pusan National University) and Dr. Philip Lee (KIST) research team recently developed a transparent conductive film composed of carbon nanotube-polyimide through a Korea-Japan joint study, and proposed a foldable solar cell applying this film.

Currently, solar cell technology is focusing on the development of the third-generation solar cells called 'Perovskite Solar Cells,' which have high photoelectric conversion efficiency and flexibility, making them notable as portable power sources. Perovskite solar cells refer to thin-film solar cells that use organic-inorganic hybrid perovskite crystal structures as the light-absorbing layer. To use them as power sources for portable devices that can be folded or bent, enhancing the flexibility of the bottom transparent electrode is an essential task. Carbon nanotubes are good electrode candidate materials that possess both flexibility and transparency, but due to internal voids and rough surfaces, there have been difficulties in using them as bottom electrodes.

The research team developed a transparent conductor that complements the gaps and rough surfaces of the mesh-like carbon nanotubes with polyimide. Polyimide fills the gaps and smooths the rough surfaces, preserving the advantages of flexible and transparent carbon nanotubes while compensating for their drawbacks. Using this, the foldable perovskite solar cells fabricated by the research team showed the highest level of photoelectric conversion efficiency (15.2%) among previously reported carbon nanotube-based flexible solar cells. In particular, under folding conditions (0.5 mm bending radius), the solar cells demonstrated high flexibility by maintaining the same performance even after 10,000 repeated cycles.

The research team also confirmed that molybdenum trioxide (MoO3), added to improve electrical conductivity, maximizes its effect under high-temperature conditions where oxygen is blocked. Thanks to the structure and thermal stability of the conductive film surrounding the carbon nanotubes, the enhancement effect on the electrode's electrical conductivity was maximized without additional processing. This is expected to provide a foundation for effectively utilizing carbon nanotubes as electrodes in highly flexible electronic devices such as foldable and rollable devices including flexible solar cells.

The research results were published on the 8th in the international journal Advanced Science. The study was conducted with support from the Leading Research Center Project, Climate Change Response Technology Development Project, and Global Frontier Project funded by the Ministry of Science and ICT and the Korea Research Foundation.

This content was produced with the assistance of AI translation services.