The Advanced Devices for Energy Conversion Lab research team in the Graduate School of Energy, Environment, Water, and Sustainability, led by Professor Jung-Yong Lee, has developed a new technique that utilizes the Marangoni effect to create an organic solar cell on a water surface. Translucent, flexible, and extremely lightweight, organic solar cells recently gathered the attention of the scientific community as an energy source for the next generation of wearable electronic devices. However, as applying the cells onto a large surface area caused difficulties in maintaining high performance, commercialization of the devices remained an elusive goal.

     The research team has succeeded in pushing the envelope of solar cell technology with their new application of the Marangoni effect. The Marangoni effect, which is also known as the “tears of wine” phenomenon, refers to the rapid mass transfer that occurs when two liquids of different surface tensions meet. Using this phenomenon, the team succeeded in creating an organic thin film that maintains its high-quality performance while covering a large surface area.

     This was achieved by dropping a polymer solution into water, resulting in the solution quickly dispersing to create a thin film on the water surface. Afterwards, the solvent evaporated or dissolved in the water to leave the uniformly thin film of polymers. This method of creating thin films has several strengths: it can create a uniform film even on curved surfaces such as paper and glass, and it can do so in a matter of seconds, which is essential in preventing oxygen absorption and subsequent damage to the film. The latter strength is crucial for fixing the main weakness of the solar cell production process, which caused significant damage to the films as they absorbed oxygen and moisture from the surrounding air during its lengthy drying process.

     Professor Lee commented, “This is a completely new and extremely quick production method to create an organic thin film of large surface area for the commercialization of organic solar cells. We are expecting this new and original technology to accelerate the commercialization process by providing cheap and highly efficient organic solar cells.”