A team, led by Mr. Chen Yongsheng, a professor from the College of Chemistry at China’s Nankai University, has made a significant breakthrough in the field of organic solar cell research. The team utilized the complementary optical strategy of oligomeric materials to construct a laminated organic solar cell with wide spectral absorption characteristics, and achieved a power conversion efficiency of 12.7%. It becomes the highest record among the reports regarding the conversion efficiency of organic/polymer solar cells. The research paper introducing the results has also been published in the international top academic journal “Nature Photonics”.
As an effective way to solve environmental pollution and energy crisis, organic solar cells are far superior to traditional solar cells – with low cost, high flexibility, simple process and environment-friendly. However, since 1958, the first organic solar cell device has been born, how to improve the efficiency of photoelectric conversion is the key challenge that perplexes scientists a lot. This issue also directly determines whether organic solar cells can run out of laboratories, and be widely used in humans’ production and life.
“As a new frontier research field, in recent years, the energy conversion efficiency of organic solar cells has gained a substantial increase,” said Prof. Chen Yongsheng. “This is mainly due to the design and development of photoactive layer materials and the constant optimization of the device structure.”
Over the years, Prof. Chen Yongsheng and his team have conducted in-depth systematic study on the selection of organic photovoltaic device materials and their construction processes, and developed a series of high-efficiency oligomer-type molecular active layer materials that can be solution-processed. Just in last year, they had already achieved a photoelectric conversion of 10%.
Considering the requirements of industrialization, utilizing active materials with different spectral absorption ranges to manufacture laminated photovoltaic devices is an effective strategy to further improve the photoelectric conversion efficiency. Based on this thinking, the researchers utilized oligomeric molecules/polymers as the front and back cell, respectively, to obtain the laminated organic photovoltaic devices with an efficiency of more than 11%.
And just recently, Prof. Chen’s team cooperated with a team at the South China University of Technology. They utilized the BDT oligomeric molecules and the porphyrin-based small molecule materials, which have good complementary absorption in the visible and near infrared regions, as donor materials of the front and the back battery unit – and adopted the solution processing method compatible with the industrial production to manufacture one type of highly efficient organic solar devices. After some process optimization, they finally achieved the verified efficiency of 12.7%.
The researchers also added that, according to the relevant design principles, and through further optimization of the materials and devices, there’s big room for the improvement of the devices’ various indicators, surely including the photoelectric conversion efficiency. And it is estimated that in the near future, the efficiency can hit more than 15%.
“What we will focus on next is to solve the issue of battery life and further improve the conversion efficiency,” said Prof. Chen. “We believe that organic solar cells can be turned into practical use from laboratories – the realization of commercial production will become a reality soon.”
It is said that this research has received strong support from the Ministry of Science, the National Natural Science Foundation, Tianjin Science and Technology Commission and Nankai University. comment