The process enables conformal, high-quality perovskite layers on micrometre-scale textured silicon wafers, meeting a key requirement for mass production. The tandem cells achieve power-conversion efficiencies above 30 per cent and maintain operational stability beyond 2,000 hours, including T90 lifetimes of more than 1,400 hours at 85 degrees Celsius under 1-sun illumination, corresponding to 1,000 watts per square metre. These performance and stability metrics place the devices among the most durable perovskite-Si tandem solar cells reported and indicate a route to commercial photovoltaic modules.
The research team is led by Assistant Professor Hou Yi, a Presidential Young Professor in the Department of Chemical and Biomolecular Engineering at the NUS College of Design and Engineering and Head of the Perovskite-based Multijunction Solar Cells Group at the Solar Energy Research Institute of Singapore (SERIS). The results are reported in the journal Science in a paper published on 19 December 2025.
For rooftop, utility-scale, and industrial solar installations, tandem cells must withstand prolonged exposure to high temperatures, humidity, and strong sunlight. Achieving such durability on industrial textured silicon wafers, rather than specialised laboratory substrates, is essential for manufacturing and certification. Although vapour deposition has been viewed as an industry-compatible approach, it had not previously yielded stable, high-quality perovskite films on true industrial silicon with large surface textures. By demonstrating this combination, the NUS team addresses a central barrier to production and shows that the devices can reach the high-temperature stability needed for deployment.
"Achieving both high efficiency and long-term durability on industrial textured silicon is essential for tandems to become commercially viable," said Asst Prof Hou.
During vapour deposition, organic perovskite precursor molecules typically have difficulty adsorbing evenly onto the steep pyramid textures characteristic of industrial silicon wafers, which leads to poor film formation and rapid degradation under heat. The NUS team designed a specialised molecule that binds to the silicon surface and promotes adsorption of organic precursors during deposition, supporting smooth perovskite film growth with the intended composition. This molecular strategy improves film quality across the textured surface and contributes to the devices' operational stability.
The resulting vapour-deposited tandem devices show strong thermal endurance. They operate stably for well over 1,000 hours under continuous illumination and retain performance during extended exposure at 85 degrees Celsius, one of the demanding accelerated ageing tests used in the solar sector. Such high-temperature stability in perovskite-based tandem cells remains uncommon and is more notable because it is demonstrated on industrial textured wafers using a scalable process.
"With vapour-deposited perovskites, we are addressing two fundamental challenges at one go: compatibility with real industrial silicon wafers and stable operation under heat," said Asst Prof Hou. "This is the first evidence of vapour-grown perovskite tandem cells achieving the required durability for commercial deployment, bringing us closer to practical and reliable tandem solar modules."
The team plans to scale the vapour-deposition technique from small-area test cells to large-area tandem modules and to integrate the process into pilot manufacturing lines. "Our next phase is to demonstrate full-size, durable tandem modules under real operating conditions," said Asst Prof Hou. "This will bring us a step closer to commercial deployment."
Research Report:Optimal perovskite vapor partitioning on textured silicon for high-stability tandem solar cells
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