Organic solar cell efficiency record: 17.3%
Chinese researchers are claiming an organic solar cell record 17.3% efficiency under standard sunlight conditions from a solution-processes structure as opposed to more-complex vacuum processing.
Over the past several years, scientists have been trying to find a way to improve the efficiency of organic photovoltaic cells, but have been stymied by the charge characteristics of organic materials. Organic materials are not only cleaner, but offer other potential benefits such as allowing for lighter-weight cells—they would also be bendable, making them useful for more applications. But they have proven to be inefficient compared to non-organic cells—some have even suggested they may never improve beyond 15 percent. Those based on silicon, by comparison, are in the 18 to 22 percent range. In this new effort, the researchers in China claim to have found a way to build an organic photovoltaic cell that tested at 17.3 percent efficiency.
The new study, led by Chen Yongsheng from Nankai University in north China’s Tianjin, proved that the organics have the potential to be just as efficient as silicon. “Low charge mobility of organic materials limited the active layer thickness and light absorption efficiency,” Chen said. His team used tandem cells, which are put together by different layers of organic materials, to address the problem. Different layers of the tandem cells can absorb different wavelengths of light. That means you can use sunlight more effectively and achieve a higher power conversion rate,” Chen said.
With further optimization of the materials, it is expected that the OPVs can achieve similar power conversion efficiency as traditional solar panels, according to the researchers.