A significant breakthrough in solar energy technology promises to revolutionize the capabilities of unmanned aerial vehicles (UAVs), commonly known as drones, and a host of other portable electronics. Researchers at the Solar Energy Research Institute of Singapore (SERIS) at the National University of Singapore (NUS) have achieved a world-record power conversion efficiency of 26.4% for a flexible perovskite-organic tandem solar cell. This unprecedented efficiency in a lightweight, adaptable form factor marks a pivotal moment for energy-autonomous devices.
The Technological Leap: Perovskite-Organic Tandem Cells
The record-breaking solar cell developed by the SERIS and NUS team is a perovskite-organic tandem solar cell. Tandem solar cells are engineered by layering multiple light-absorbing materials, each designed to capture different parts of the solar spectrum, thereby maximizing the conversion of sunlight into electricity. In this particular innovation, a perovskite top cell is combined with an organic bottom layer. Perovskite materials have rapidly emerged as a game-changer in the solar industry due to their exceptional efficiency potential and flexibility, while organic semiconductors offer tunability in their bandgaps.
The core innovation driving this record efficiency lies in a newly designed narrow-bandgap organic absorber layer within the tandem cell. This novel absorber significantly enhances the harvesting of near-infrared (NIR) photons, which has historically been a challenging bottleneck for thin-film tandem solar cells. By efficiently capturing more of the solar spectrum, the device can convert a greater amount of light into electrical energy. The researchers reported a power conversion efficiency of 26.4% over a 1 cm² active area, a result that has been independently certified. Notably, even higher efficiencies were achieved on smaller samples, with 27.5% recorded on 0.05 cm² devices and 26.7% on 1 cm² devices in laboratory settings. This 26.4% certified figure represents the highest performance to date among perovskite-organic, perovskite-CIGS, and single-junction perovskite cells of comparable size.
Advancements in Flexible Solar Technology
Flexible solar cells represent a significant departure from traditional rigid silicon-based panels. They are created by depositing thin layers of photovoltaic material onto flexible substrates, making them considerably thinner and lighter. This characteristic is crucial for applications where weight and conformity to irregular surfaces are paramount. Perovskite solar cells, in particular, are at the forefront of this flexible revolution due to their ability to be manufactured into ultra-thin and lightweight designs while maintaining high efficiency.
Previous advancements in flexible solar technology have demonstrated impressive results, although generally below this latest record. For instance, in April 2025, researchers at Tokyo City University developed a flexible solar cell combining a semi-transparent inverted perovskite top cell with a flexible silicon heterojunction bottom cell, achieving a 26.5% efficiency. Chinese researchers also achieved a 24.6% efficiency with a flexible tandem solar cell in June 2025, demonstrating remarkable durability by maintaining over 90% performance after 3,000 folds and 320 hours of operation. Earlier in April 2025, Korean researchers reported a world record of 23.64% efficiency for a flexible perovskite-CIGS tandem solar cell, emphasizing its excellent durability, retaining 97.7% of its initial efficiency after 100,000 bending cycles. These continuous improvements underscore the rapid progress in flexible solar cell research.
Empowering Drones and Beyond with Solar Autonomy
The implications of SERIS’s 26.4% efficient flexible solar cell are particularly profound for the field of autonomous drones. Current drone operations are often limited by battery life, necessitating frequent recharging or battery swaps, which restricts their endurance and operational range. Integrating these ultra-lightweight, high-efficiency flexible solar cells can significantly extend flight times and enable energy-autonomous operation, reducing the need for manual intervention.
The benefits for drones are multifaceted:
- Extended Endurance: By continuously harvesting solar energy, drones can remain airborne for much longer periods, facilitating extended missions for surveillance, delivery, environmental monitoring, or infrastructure inspection.
- Reduced Weight: The ultra-lightweight nature of these perovskite solar cells is critical for drones, where every gram impacts performance and payload capacity. They can contribute as little as 1/400th of a drone’s total weight.
- Flexible Integration: The ability of these cells to be seamlessly integrated onto curved or irregular surfaces, such as drone wings or bodies, opens up new design possibilities for solar-powered UAVs.
- Cost-Effectiveness and Sustainability: As the technology advances towards pilot-line manufacturing, these cost-effective and environmentally friendly solar solutions can provide a sustainable power source, reducing reliance on traditional batteries that pose disposal challenges.
Beyond drones, the lightweight and flexible form factor of these perovskite-organic tandem solar cells makes them ideally suited for a wide array of other applications. These include wearable electronics, smart fabrics that can monitor biometrics, self-powered health patches, and various AI-enabled devices that require continuous and on-device power generation. Their potential for roll-to-roll production also suggests future large-scale, cost-effective manufacturing, paving the way for widespread adoption.
Challenges and Future Trajectories
While the efficiency milestone is a significant achievement, research continues to address challenges related to the long-term operational stability of perovskite solar cells in real-world conditions. Perovskite devices can be sensitive to environmental factors such as moisture and heat, although 2D perovskites have shown improved thermal and moisture stability. Ongoing research focuses on enhancing the durability and robustness of these cells to ensure consistent performance over extended periods.
Furthermore, the next phase of research will concentrate on advancing towards pilot-line manufacturing. Scaling up production from laboratory samples to commercial quantities is a crucial step for bringing this high-performance, flexible solar technology to market. Scientists are optimistic about the future, with projections that efficiencies for these flexible films could exceed 30%, making them even more competitive with traditional solar technologies.
The development of flexible solar cells with such high efficiencies represents a transformative advancement in renewable energy. This breakthrough not only promises to extend the reach and utility of autonomous drones but also opens up a myriad of possibilities for portable, self-powered devices across various sectors, heralding a new era of versatile and efficient solar energy harvesting.
