An international research team, led by Professor Dr. Antonio Abate, has achieved a significant breakthrough in perovskite solar cell technology, boosting their efficiency to almost 27% while dramatically enhancing their long-term stability with the application of a novel fluorinated coating. This advancement addresses a critical hurdle in the commercial viability of next-generation solar cells, paving the way for more durable and high-performing devices.
A Leap Forward in Perovskite Technology
The research, published in Nature Photonics, details how the innovative coating has enabled perovskite solar cells to operate continuously for 1,200 hours under standard illumination without any observed decrease in efficiency. This 1,200-hour benchmark is equivalent to approximately one year of outdoor use, a crucial indicator for real-world application. Before this development, comparison cells without the new “Teflon-like” layer experienced a 20% efficiency drop in just 300 hours. The new efficiency mark of almost 27% represents the current state-of-the-art for this technology.
The “Teflon-Like” Coating Explained
The key to this breakthrough lies in a fluorinated compound that forms an almost monomolecular film at the interface between the perovskite surface and the top contact layer. This ultra-thin, “Teflon-like” molecular layer acts as a chemical protective barrier. As explained by Professor Abate, the compound slides between the perovskite and the buckyball (C60) contact layer, effectively isolating the sensitive perovskite layer from the adjacent contact layer. This isolation prevents defects and losses, allowing electricity to flow freely while chemically shielding the perovskite from degradation. Furthermore, this intermediate layer improves the structural stability of both adjacent layers, particularly the C60 layer, making it more uniform and compact.
Overcoming the Stability Challenge
While perovskite solar cells are known for their high power conversion efficiency and low production costs, their rapid degradation and insufficient stability have been major obstacles to widespread adoption. The newly developed coating directly tackles this issue by preventing the chemical reactions that typically lead to defects and a decline in performance. In addition to extended operational stability, the coating also demonstrated exceptional thermal stability, enduring 1,800 hours at 85 °C and over 200 cycles between –40 °C and +85 °C. The perovskite solar cells used in this study featured an inverted (p-i-n) structure, which is particularly well-suited for integration into tandem cells, such as those combined with silicon cells.
Implications for Solar Energy’s Future
The combination of high efficiency and significantly improved stability positions perovskite solar cells closer to commercial viability. This advancement could lead to the development of more efficient and durable solar panels, potentially offering a low-cost alternative to traditional silicon-based photovoltaics. The ability to maintain high efficiency over extended periods under various environmental conditions is crucial for accelerating the industrial development and broader market application of perovskite technology.
Broader Advances in Perovskite Research
The field of perovskite solar cells is experiencing rapid progress, with several institutions reporting impressive achievements:
- Oxford University scientists have also developed an ultra-thin, flexible material using a multi-junction approach, achieving over 27% efficiency, independently certified by Japan’s National Institute of Advanced Industrial Science and Technology (AIST). This approach involves stacking multiple light-absorbing layers to harness a wider spectrum of light, with expectations of exceeding 45% efficiency over time.
- Northwestern University researchers developed an amidinium-based protective coating that enhances both efficiency and lifespan, making the cells ten times more resistant to decomposition compared to traditional ammonium-based coatings. Their cells demonstrated 26.3% efficiency and tripled the T90 lifetime (the time to lose 90% of initial efficiency) under extreme conditions.
- A research team at the Institute of Semiconductors of the Chinese Academy of Sciences achieved a photoelectric conversion efficiency of 27.2% and significantly enhanced operational stability by introducing alkali metal oxalate during film growth to achieve a homogenized vertical distribution of chlorine. These cells maintained 86.3% of their initial efficiency after 1529 hours of continuous operation.
- Scientists from the National University of Singapore (NUS) developed a three-layer, triple-junction tandem solar cell with a certified world-record efficiency of 27.1%.
- Researchers at the Southern University of Science and Technology achieved a record efficiency of 27.30% under 5.9 sun illumination for a single-junction perovskite solar cell by utilizing an ultrafast hot hole transfer with phthalocyanine derivatives.
- Further research highlights the potential for efficiencies beyond 27%, with studies exploring innovative inorganic perovskites like Sr3PI3 in charge transport layers, showing simulation results for 27.32% PCE.
Outlook: Towards Commercialization
These ongoing advancements across different research fronts underscore the immense potential of perovskite solar cells to revolutionize renewable energy. With continuous improvements in both efficiency and stability, particularly with breakthroughs like the new fluorinated coating, perovskite technology is moving steadily from laboratory experiments towards practical, large-scale commercial applications.
