Shanghai, April 20 (Editor Huang Junzhi) According to reports, researchers at the University of Wuppertal in Germany recently developed an organic perovskite solar cell with low interface loss and high open circuit voltage.
The device has an open-circuit voltage of 2.15 V, a short-circuit current of 14.0 mA cm, and a fill factor of 80%.
Most proudly, this new perovskite organic tandem solar cell has a photoelectric conversion efficiency of 24%, setting a new world record, while its thickness is only 1 m.
Researcher Kai Brinkmann said, "Our solar cells can be machined on almost any smooth substrate one can think of – from the front of a building to the roof, to the back of a phone, to plastic foil, and even integrated into clothes." ”
As we all know, traditional solar cell technology is mainly based on semiconductor silicon, which is now considered to have "reached the limit of performance". Therefore, it is very important to develop new solar technologies that make a decisive contribution to the energy transition. The results of these studies have recently been published in the journal Nature.
In the new study, the researchers combined two alternative absorbent materials. They used organic semiconductors, a carbon-based compound that can conduct electricity under certain conditions. It is then paired with perovskites based on lead halogen compounds, which have excellent semiconductor properties.
Since sunlight is made up of different spectral components (i.e. colors), efficient solar cells must convert as much sunlight as possible into electricity. This can be achieved through so-called tandem cells, in which different semiconductor materials are combined in solar cells, each absorbing a different range of the solar spectrum.
It is understood that in the current study, organic semiconductors are used in the ultraviolet and visible parts of light, while perovskites can effectively absorb near-infrared light. Similar combinations of materials have been explored in the past, but now the research team has successfully improved their performance.
The researchers explain that in order to achieve such a high conversion efficiency, the interface loss between materials inside the solar cell must be minimized. To solve this problem, scientists have developed a so-called "interconnect" that couples organic and perovskite cells electronically and optically.
As an interconnection, a thin layer of indium oxide is integrated into the solar cell, which is only 1.5 nanometers thick to minimize losses. Simulation results show that in the future, a series cell with an efficiency of more than 30% can be achieved through this method.
"When we started this project, the world's best perovskite/organic tandem batteries had an efficiency of about 20 percent," the researchers said. Now, our efficiency is 24%, and simulations have shown that our concept should allow us to be more efficient than 30%. ”