NUS Sets New Benchmark in Solar Efficiency with Innovative Tandem Cell

In a significant advancement for renewable energy technology, researchers at the National University of Singapore (NUS) have achieved a world record in solar power conversion efficiency, demonstrating a perovskite-organic tandem solar cell with a certified efficiency of 26.4% over a 1 cm² active area. This breakthrough, published in the prestigious journal *Nature* on June 25, 2025, represents a pivotal moment in solar technology, potentially transforming energy applications across various sectors.

The innovative design is led by Assistant Professor Hou Yi, a Presidential Young Professor in the Department of Chemical and Biomolecular Engineering at NUS, who heads the Perovskite-based Multijunction Solar Cells Group at the Solar Energy Research Institute of Singapore (SERIS). The research team's achievement marks a significant milestone in the quest for more efficient solar energy solutions, particularly encouraging given the growing global emphasis on sustainable energy sources.

Historically, perovskite-organic tandem cells have struggled with low efficiency in harnessing near-infrared (NIR) photons, which has limited their performance compared to traditional solar cells. However, the NUS team tackled this challenge by developing a new narrow-bandgap organic absorber that enhances NIR photon harvesting, thereby addressing a long-standing bottleneck in thin-film tandem solar cells. According to the research findings, this new design allows for efficient absorption of light in the NIR region while facilitating effective charge separation and promoting ordered molecular packing.

The tandem solar cell's efficiency was rigorously tested, achieving a record 27.5% on smaller samples and maintaining a certified efficiency of 26.4% on larger units, surpassing previous benchmarks for similar devices. Asst Prof Hou explains, "With efficiencies poised to exceed 30%, these flexible films are ideal for roll-to-roll production, making them suitable for applications in advanced technologies such as smart textiles and wearable electronics."

The implications of this research extend beyond just efficiency figures. The ability to produce lightweight, flexible solar cells could revolutionize the integration of solar power into everyday items, enhancing energy independence and sustainability in various consumer products. Asst Prof Hou envisions applications ranging from self-powered health monitoring devices to smart fabrics that can generate energy without bulky batteries, suggesting a future where solar technology is seamlessly woven into daily life.

Looking ahead, the NUS team plans to focus on improving the operational stability of these solar cells under real-world conditions and advancing towards pilot-line manufacturing. These steps are crucial for scaling up production and bringing high-performance solar technology to market, which will be essential in meeting global energy demands and combating climate change.

The NUS breakthrough aligns with broader international efforts toward sustainable energy solutions. The World Bank and International Energy Agency have emphasized the importance of solar energy in achieving net-zero emissions goals, and innovations like these are vital in propelling the solar industry forward. As solar energy continues to gain prominence in the global energy mix, advancements such as those made by the NUS team will play a crucial role in shaping the future of energy generation and consumption.

In conclusion, the achievement by NUS not only sets a new standard for solar efficiency but also opens up numerous possibilities for the application of solar technology in various sectors. The ongoing research and future developments in this area are expected to significantly contribute to the global transition towards renewable energy sources, illustrating the crucial intersection of innovation, sustainability, and technology in addressing the challenges of climate change.