Gwangju Institute of Science and Technology (GIST) said on the 23rd that a joint team led by Kang Hong-gyu, principal researcher at the Next-Generation Energy Research Institute, and Lee Gwang-hee, a professor in the Department of Materials Science and Engineering, has developed a fundamental technology that can greatly improve both the transparency and power generation efficiency of next-generation semitransparent organic solar cells.
Semitransparent organic solar cells are a type of organic solar cell that generates electricity from light and can transmit part of the visible spectrum, making them suitable for use in windows or building cladding. They can also be applied to building-integrated photovoltaics, vehicle-mounted photovoltaics, and portable electronic devices.
However, due to the nature of the semitransparent structure, increasing transparency reduces power generation efficiency, and increasing power generation efficiency reduces transparency, making it difficult to satisfy both performance metrics at the same time.
To solve this problem, the team reduced the content of the "electron donor," a material that absorbs visible light, to increase transparency and instead introduced an additive that helps maintain smooth electrical pathways. The additive creates paths on the electrode surface that allow current to flow well.
As a result, they achieved an average visible light transmittance of 37.53% and a power conversion efficiency of 10.7%. Average visible light transmittance indicates how much light in the visible range passes through the solar cell, and power conversion efficiency indicates how much solar energy can be converted into electrical energy. They also recorded a top-tier 4.01% in light utilization efficiency (the product of average visible light transmittance and power conversion efficiency), demonstrating high performance among semitransparent organic solar cells under the same conditions.
This achievement presents a new design strategy that secures both transparency and power generation efficiency with a simple device architecture, rather than relying on the conventional complex multilayer structures, proving that semitransparent organic solar cells are a next-generation energy technology suitable for real-world applications.
Kang Hong-gyu said, "This study is significant in that it resolves the long-standing trade-off between transparency and efficiency in semitransparent organic solar cells," adding, "If integrated with transparent structures such as building windows or vehicle glass going forward, it could greatly contribute to urban eco-friendly energy self-sufficiency."
The findings were published online on Aug. 21 in the international journal "Journal of Materials Chemistry A," and were recognized as noteworthy, being selected as a "Hot Paper."
References
Journal of Materials Chemistry A (2025), DOI: https://doi.org/10.1039/D5TA03918E