IIT Roorkee develops 30% efficient tandem solar cells

India’s renewable energy ambitions have received a significant boost with a breakthrough by the Indian Institute of Technology (IIT) Roorkee in solar technology. A research team led by Prof. Soumitra Satapathi has successfully developed silicon-perovskite tandem solar cells achieving a record 30% power conversion efficiency (PCE), surpassing the approximately 24% efficiency of conventional silicon modules. The team anticipates that further optimization could push efficiency as high as 35%.

Crystalline silicon (c-Si) solar cells have dominated the global market for over four decades, but their efficiency is approaching the theoretical limit, and their production carries a heavy energy footprint. India’s dependence on imported silicon modules underscores the need for indigenous high-efficiency solutions. The silicon-perovskite tandem technology combines silicon’s established performance with the tunable absorption properties of perovskite, enabling broader sunlight capture and increased energy conversion.

Prof. Satapathi, known as the “Solar Man of India” for his pioneering work on Jamun-based low-cost solar cells, has led perovskite research for more than a decade. His team fabricated four-terminal tandem solar cells using a wide-bandgap perovskite top cell (~1.8 eV) layered over a silicon bottom cell. This design allows each layer to operate independently at maximum efficiency, capturing complementary parts of the solar spectrum.

The researchers are scaling this technology for commercial wafer sizes, including G12 and G12R, using slot-die coating, a scalable technique for producing perovskite mini-modules. Large-area prototypes are in development, targeting 32% efficiency on full-sized modules within the next year. These advancements aim to establish India as a global hub for tandem photovoltaic technology.

To facilitate commercialization, the team has launched Perovskite Innovation Pvt. Ltd., a startup dedicated to silicon-perovskite tandem solar technology. The venture supports Make in India and Atmanirbhar Bharat initiatives, seeking to reduce import dependence, foster domestic manufacturing, and accelerate green economic growth.

IIT Roorkee’s credibility enhances the impact of the breakthrough. Prof. Satapathi’s leadership, the institute’s long-standing expertise in advanced materials, and a proven track record of translating lab innovations to market-ready technologies lend confidence that the tandem cells can achieve commercial viability.

The technology positions India competitively on the global stage. While conventional silicon modules achieve ~24% efficiency, IIT Roorkee’s tandem cells already reach 30%, with the potential for 35%. Perovskite-based manufacturing is cost-effective and scalable, allowing for higher electricity yield per unit area and reduced production costs.

Commenting on the development, Prof. Satapathi said: Our silicon-perovskite tandem solar cells have the potential to transform India’s renewable energy landscape. By pushing efficiency beyond global benchmarks and ensuring indigenous development, we are not just building solar panels, we are building India’s energy independence.

The breakthrough represents a strategic step toward technological sovereignty, energy self-reliance, and global leadership in clean energy innovation. With a path from lab-scale prototypes to large-area commercial modules, IIT Roorkee’s development underscores India’s growing capability in next-generation solar technology.