Researchers from South Korea’s state-run science laboratory have developed highly elastic thread-like solar cells, a breakthrough that may be used in next-generation wearable technologies such as clothes that can charge on its own without the need of a heavy battery.
A research team led by Lee Joong-kee, a principal researcher at the Center for Energy Convergence Research of the Korea Institute of Science and Technology (KIST), announced Monday that they developed a thread-like dye-sensitized solar cell and elevated the photoelectric conversion efficiency using sunlight to 8.1 percent. It is the highest level of efficiency ever recorded for thread-like solar cells in the world, according to the institute.
The yarn-type solar cell has a titanium (Ti) wire with the diameter of 250μm wrapped in a transparent tube. To enhance efficiency, the researchers oxidized the Ti wire’s surface into minute patterns and increased an area where the cell is exposed to sunlight.
The cell’s output voltage currently stands at only 0.7V, half the level of a commercial mercury cell that is used in a small watch. However, the battery shows high elasticity and excellent shape recovery with a performance retention of over 95 percent when it was rolled up around a straw, which is one centimeter in diameter, indicating its potential to be woven into textiles. “This technology could be the beginning of developing a new wearable device that would be placed inside clothes,” Lee said. Their latest findings were published in the July edition of the international science journal Nano Energy.