Researchers in Australia have developed the largest and most efficient triple-junction perovskite-perovskite-silicon solar cell to date, a significant achievement that addresses key barriers to the commercialization of next-generation solar technology. The team, led by scientists at the University of Sydney, created a device that not only sets a new global record for power conversion efficiency at its size but also demonstrates remarkable durability under harsh testing conditions, signaling a major advance in the quest for more sustainable energy solutions.
The work tackles the dual challenge that has long hindered perovskite solar cells: scaling up the technology without losing efficiency and ensuring the devices can withstand real-world environmental stresses over long periods. By achieving a certified 23.3% efficiency on a 16 cm² cell, the researchers have shown that high performance is possible on a surface area relevant to manufacturing, while a smaller version of the cell became the first of its kind to pass a rigorous international standard for thermal stability. This combination of size, efficiency, and resilience represents a critical step toward making perovskite tandem technology a viable competitor to conventional silicon-based solar panels.
New Benchmarks in Efficiency and Scale
The Australian-led team’s primary achievement is the creation of a 16-square-centimeter triple-junction cell with an independently certified steady-state power conversion efficiency of 23.3%. This figure is the highest ever reported for a large-area device of this type, a crucial metric for evaluating the practical potential of a new solar technology. While laboratory-scale cells often achieve high efficiencies, translating that performance to larger surfaces is a persistent challenge in solar research. Successfully fabricating a cell of this size suggests that the manufacturing processes are becoming more refined and scalable.
Alongside the large-area device, the researchers also produced a smaller 1-square-centimeter cell that recorded an efficiency of 27.06%. This smaller cell was instrumental in testing the fundamental limits and durability of the new design. The high efficiency levels achieved in both sizes underscore the potential of perovskite materials to exceed the performance of traditional silicon technologies when engineered in a multi-junction structure.
Engineering for Unprecedented Durability
Perhaps more significant than the efficiency record is the cell’s proven resilience. Perovskite materials are notoriously susceptible to degradation from moisture and temperature fluctuations, a weakness that has been a major barrier to their widespread adoption. The University of Sydney team has made a breakthrough in this area, with their 1 cm² prototype becoming the first in the world to pass the stringent Thermal Cycling test administered by the International Electrotechnical Commission (IEC).
This demanding test subjects the solar cell to 200 cycles of extreme temperature swings, from -40 to 85 degrees Celsius. Passing this test is a key benchmark for certifying that a solar panel can survive in real-world operating conditions over many years. Furthermore, the prototype demonstrated impressive longevity under operational stress. In a separate test, the cell retained 95% of its initial efficiency after more than 400 hours of continuous operation under light, directly addressing concerns about the material’s long-term stability.
The Science Behind the Breakthrough
Chemical and Structural Innovations
The record-setting performance was achieved by re-engineering both the perovskite chemistry and the overall design of the triple-junction cell. Professor Anita Ho-Baillie, who led the study from the University of Sydney Nano Institute and School of Physics, explained that the team focused on improving the intrinsic stability of the perovskite material itself. A key innovation involved replacing the commonly used and less stable methylammonium compound in the perovskite crystal lattice with rubidium. This substitution creates a more robust lattice that is less prone to developing defects and degrading over time.
The researchers also developed a new surface treatment to further enhance stability. They replaced lithium fluoride, a less stable compound, with piperazinium dichloride. This change helped to fortify the interfaces between the different layers of the solar cell, improving both performance and resilience. These chemical modifications were crucial to minimizing energy loss and preventing the rapid degradation that has plagued earlier generations of perovskite cells.
Harnessing the Solar Spectrum
The device’s triple-junction structure is fundamental to its high efficiency. It uses three interconnected semiconductors, each designed to absorb a different portion of the solar spectrum. The cell consists of two different perovskite layers stacked on top of a conventional silicon base. The top perovskite layer is tuned to capture high-energy blue light, the middle perovskite layer absorbs green and yellow light, and the bottom silicon layer captures lower-energy red and infrared light. This division of labor allows the cell to convert a much broader range of the sun’s energy into electricity compared to a single-junction silicon cell, pushing theoretical efficiency limits higher.
Implications for Commercial Viability
Perovskite materials have long been hailed for their potential to revolutionize solar energy. They are more cost-effective to produce than highly purified silicon and can capture more of the solar spectrum. However, the twin challenges of poor stability and difficulty in scaling up have kept the technology confined primarily to laboratories. This latest advance from the University of Sydney directly confronts these barriers, demonstrating a clear and credible path toward overcoming them.
By proving that large, stable, and highly efficient perovskite tandem devices are possible, the research paves the way for the next phase of development and potential commercialization. The ability to pass the IEC thermal cycling standard is a particularly important milestone, as it meets a critical requirement for market entry. As the world seeks to accelerate the transition to renewable energy, innovations that make solar power cheaper, more efficient, and more durable are essential. This breakthrough suggests that perovskite-based technology is moving closer to becoming a cornerstone of the global energy supply.