Stretchable solar cells that can withstand strain have drawn much attention as a potential energy source since the market for wearable electronics is expanding quickly. Such solar cells require their photoactive layer, which turns light into energy, to have great electrical performance and mechanical flexibility to be constructed. However, it is difficult to meet both of these conditions, which makes the development of flexible solar cells tough.
Chemical structure of the newly developed conductive polymer and performance of stretchable organic solar cells using the material. Image Credit: Korea Advanced Institute of Science & Technology
The world’s highest-performing stretchable organic solar cell was unveiled on December 26th, 2023 by a KAIST research team from the Department of Chemical and Biomolecular Engineering (CBE), headed by Professor Bumjoon Kim. The team also announced the creation of a new conductive polymer material that attained high electrical performance and elasticity.
Organic solar cells are devices in which the photoactive layer, which converts light into energy, is made of organic materials. They are lighter and more flexible than conventional non-organic material-based solar cells, making them ideal for wearable electrical devices.
Solar cells are crucial for manufacturing electrical devices as an energy source; however, high-efficiency solar cells sometimes lack flexibility, limiting their applicability in wearable devices to this point.
Through chemical bonding, the team led by Professor Kim coupled a highly stretchable polymer to an electrically conductive polymer with good electrical characteristics, creating a novel conductive polymer with both electrical conductivity and mechanical stretchability.
This polymer achieves the greatest recorded photovoltaic conversion efficiency (19%) utilizing organic solar cells, while simultaneously being 10 times stretchable as previous devices. As a result, the researchers created the world’s best-performing stretchable solar cell, which can be stretched up to 40% during operation, and proved its application for wearable devices.
Through this research, we not only developed the world’s best performing stretchable organic solar cell, but it is also significant that we developed a new polymer that can be applicable as a base material for various electronic devices that need to be malleable and/or elastic.
Bumjoon Kim, Professor, Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science & Technology
This study was published in Joule on December 1st, 2023, and it was carried out by KAIST researchers Jin-Woo Lee and Heung-Goo Lee as first co-authors in collaboration with teams directed by Professors Taek-Soo Kim from the Department of Mechanical Engineering and Sheng Li from the Department of CBE.
The National Research Foundation of Korea provided funding for this study.
Journal Reference:
Lee, J.-W., et. al. (2023) Rigid- and soft-block-copolymerized conjugated polymers enable high-performance intrinsically stretchable organic solar cells. Joule. doi:10.1016/j.joule.2023.11.005