A European team of scientists have achieved a new solar efficiency record by combining silicon- with perovskite-based solar cells.
According to the EPFL and CSEM team, their innovative yet simple manufacturing technique could be directly integrated into existing production lines, helping raise efficiency to above 30%.
Silicon-based solar cells make up 90% of the market. In terms of cost, stability and efficiency (20-22% for a typical solar cell on the market), they are well ahead of the competition. However they are nearing their maximum theoretical efficiency.
This has fueled researchers to create new concepts to help them achieve a long-term reduction in solar electricity prices and wider adoption of photovoltaic technologies.
One possible solution is to place two different types of solar cells on top of each other to maximize the conversion of light rays into electrical power.
Though these ‘double-junction’ cells are being widely researched in the scientific community, they are too expensive to make.
Now research teams from EPFL’s Photovoltaics Laboratory and the CSEM PV-center have developed an economically competitive solution by integrating a perovskite cell directly on top of a standard silicon-based cell, obtaining a record efficiency of 25.2%.
The researchers contend that their production method is promising as it adds only a few extra steps to the current silicon-cell production process, reducing costs significantly.
In tandem cells, perovskite complements silicon: it converts blue and green light more efficiently, while silicon is better at converting red and infra-red light.
“By combining the two materials, we can maximize the use of the solar spectrum and increase the amount of power generated. The calculations and work we have done show that a 30% efficiency should soon be possible,” say the study’s main authors Florent Sahli and Jérémie Werner.
Image and content credits: École polytechnique fédérale de Lausanne (EPFL)