4 terminal perovskite-silicon PV tandem devices hit 30% efficiency

• TNO, TU Eindhoven, imec as well as TU Delft, partners in Solliance, joined forces to further push the conversion effectiveness of tandem solar cells to past the limits these days's commercial solar (PV) modules.

For the very first time, four-terminal perovskite/silicon tandem devices with a certified top cell passed the obstacle of 30%. Such high efficiency enables even more power per square meter and much less price per kWh. The result exists throughout the 8th World Seminar on Photovoltaic Energy Conversion (WCPEC-8) in Milan, and it has been accomplished by combining the emerging perovskite solar cell with conventional silicon solar cell modern technologies. The perovskite cell, which features transparent contacts and also belongs to the tandem stack, has been independently accredited.

Additionally, achieving high-power density will certainly create a lot more possibilities to integrate these solar cells right into building and building elements, to ensure that even more existing area can be covered with PV modules. Damaging the 30% barrier is consequently a big step in accelerating the energy transition and also boosting energy security by decreasing the dependence on fossil fuels.

The very best of both world

Tandem devices can reach greater performances than solitary junction solar cells because of a much better utilization of the solar spectrum. The presently emerging tandems integrate commercial silicon innovation for the bottom device with perovskite modern technology: the latter including very effective conversion of ultraviolet and visible light and outstanding openness to near infrared light.

In four-terminal (4T) tandem devices the top and bottom cells operate independently of each other, that makes it possible to apply various lower cells in this type of devices. Commercial PERC technology as well as premium modern technologies like heterojunction or TOPCon or thin-film technology such as CIGS can be implemented in a 4T tandem device with hardly any adjustments to the solar cells. Moreover, the four-terminal architecture makes it simple to implement bifacial tandems to more increase the energy return.

Researchers from the Netherlands and Belgium have efficiently boosted the performance of the semi-transparent perovskite cells as much as 19.7% with a location of 3x3 mm2 as licensed by ESTI (Italy). "This type of solar cell features a highly transparent back get in touch with that enables over 93% of the close to infrared light to reach the bottom device. This performance was attained by maximizing all layers of the semi-transparent perovskite solar cells making use of sophisticated optical as well as electrical simulations as an overview for the speculative work in the lab," says Dr. Mehrdad Najafi of TNO.

" The silicon device is a 20x20-mm2 large, heterojunction solar cell featuring enhanced surface passivation, transparent conductive oxides and also Cu-plated front get in touches with for modern provider removal" states Yifeng Zhao, Ph.D. student at TU Delft, whose results have actually been recently published in Progress in Photovoltaics: Research and also Applications. The silicon device optically piled under the perovskite adds with 10.4% effectiveness points to the complete solar energy conversion.

Combined, 30.1% is the conversion effectiveness of this non-area matched 4T tandem devices operating individually. This globe's best effectiveness is measured according to generally approved procedures.

Future of 4 terminal tandem PV modules

This is not all: Incorporating this very transparent perovskite cell with other silicon-based modern technologies, such as back call (metal wrap via and also interdigitated back get in touch with cells) and TOPCon solar cells, has likewise supplied conversion performances coming close to 30%. This demonstrates the possibility of very transparent perovskite solar cells as well as their flexibility to be incorporated with already commercialized modern technologies.

These globe best performances acquired on a multitude of incumbent innovations is a more landmark towards commercial release. "Currently we know the ingredients and are able to regulate the layers that are needed to reach over 30% effectiveness. Once combined with the scalability competence and also knowledge gathered in the past years to bring material and processes to big area, we can focus with our industrial partners to bring this modern technology with effectiveness past 30% into mass production" claims Prof. Gianluca Coletti, Program Manager Tandem PV modern technology as well as application at TNO.