Breakthrough: Perovskite Tandem Solar Cell Achieves 30.9% Efficiency

Researchers at EPFL in Switzerland have made a significant breakthrough in the field of solar energy with their latest demonstration of a tandem silicon perovskite photovoltaic cell design. By combining additive and substrate engineering, the team has achieved consistently high power conversion efficiencies that could revolutionize the solar energy industry.

Perovskite silicon (Si) tandem solar cells have emerged as strong contenders to replace the single-junction Si cells currently dominating the market. EPFL has already set a new efficiency record of 31.25% with their tandem cell design, showcasing the immense potential of this technology.

One of the key challenges in integrating perovskite cells with Si is justifying the additional cost involved. For these tandem devices to be commercially viable, they must demonstrate significantly high power conversion efficiencies to make them competitive in the market.

Machine learning has played a crucial role in accelerating the discovery and development of solar-cell perovskites. The researchers at EPFL have leveraged this technology to enhance the efficiency of their tandem devices, paving the way for more efficient and cost-effective solar energy solutions.

The team at EPFL improved the efficiency of their tandem devices by spin coating a perovskite material onto front-side flat silicon wafers. By incorporating 2,3,4,5,6-pentafluorobenzylphosphonic acid (pFBPA) in the precursor ink, they were able to suppress recombination near the perovskite/C60 interface, leading to higher open-circuit voltage (Voc) and fill factor (FF) without the need for additional passivating layers.

Another key development involved the use of sparsely coated SiO2 nanoparticles (NPs) as an interlayer between the perovskite and the hole transport layer (HTL). This innovative approach helped reduce the number of pinholes and shunts introduced by pFBPA, further enhancing the fill factor of the devices.

By integrating these advancements into an optically and electrically optimized tandem device, the researchers were able to achieve reproducible power conversion efficiencies of 30 ± 1%, with a certified maximum efficiency of 30.9%. These results mark a significant milestone in the quest for more efficient and sustainable solar energy technologies.

For more information, visit www.epfl.ch