Researchers from the Fraunhofer Institute for Solar Energy Research (ISE) in Freiburg, Germany, have teamed up with scientists at AMOLF in Amsterdam, Netherlands. Together, they have achieved a remarkable milestone in solar cell efficiency.
The researchers have successfully fabricated a multijunction solar cell based on silicon with an efficiency of 36.1%. This is the highest solar panel efficiency ever recorded.
This groundbreaking feat was recently presented at the European Photovoltaic Solar Energy Conference in Lisbon, Portugal.
The collaboration between ISE and AMOLF, which began in 2020, has proven to be fruitful. ISE has expertise in developing high-efficiency solar cells using silicon and III-V semiconductors, such as GaInP or GaAs. Meanwhile, AMOLF is proficient in light management optimization.
Throughout the project, the solar cells traveled between Freiburg and Amsterdam to undergo different processing steps. This culminated in the successful creation of the full solar cell.
The collaboration benefitted from AMOLF’s innovative back reflector and ISE’s improved GaInAsP middle cell. Both technologies contributed to this extraordinary outcome.
Traditional silicon-based solar cells have inherent limitations, with a maximum energy conversion efficiency of 29.4 percent. This limitation can be overcome by employing a multijunction design.
In a multijunction design, multiple light absorption layers are stacked to enhance the efficiency. The stacked layers effectively use different parts of sunlight’s color spectrum.
The newly achieved record efficiency is the result of combining a state-of-the-art “silicon TOPCon” solar cell with two semiconductor layers. One semiconductor layer is made of gallium, indium, and phosphide. The other is made of gallium, indium, arsenide, and phosphide.
In the diagram above, the silicon TOPCon layer is standing upright. The semiconductor layers are lying flat.
According to optics.org, all of these components were manufactured at ISE.
After assembly, the layer stack is then covered with a metal/polymer nanocoating specially designed at AMOLF and jointly fabricated at AMOLF and ISE. The back reflector enhances the capture of light within the solar cell, enabling the efficiency to exceed 36 percent.
The assembly of these ultra-high efficiency multijunction cells is currently more expensive compared to traditional silicon solar cells. Nevertheless, the multijunction cells are extremely beneficial for applications that require a significant amount of solar power generation in a small area.
Potential applications of the multijunction cells include solar-powered electric cars, consumer products, and drones. Furthermore, the new light management design can also be used in other types of solar cells, including silicon-perovskite cells.
In July, scientists obtained a solar panel efficiency of 32.5%, setting a new record. The fact that this record has been broken just two months later highlights how rapidly solar technology is improving.
Image Source: pv magazine, https://shorturl.at/bEV19
