Researchers engineered a dual-interface carrier transport strategy for monolithic perovskite and copper indium gallium selenide tandem solar cells, achieving 31.09% efficiency in small devices, Nature Energy reported.
Interfacial optical and electronic losses have historically restricted monolithic tandem solar cells below their theoretical efficiency limits. These tandem devices layer a wide-bandgap perovskite top cell over a lower-bandgap bottom cell to capture broader light spectrums than single-junction cells.
Carrier Transport Strategy
To address interfacial losses, the team combined a nanoparticle-assisted nickel oxide intermediate recombination layer with bimolecular co-passivation at the perovskite and C60 interface. This design enabled conformal coverage on textured bottom surfaces, reduced defects, optimized band alignment, and improved carrier extraction across both interfaces.
In small-area test devices measuring 0.0539 square centimeters, champion cells achieved a peak power conversion efficiency of 31.09%. Certified testing recorded 30.57% efficiency for these devices, alongside a steady-state efficiency of 30.32%.
For larger devices measuring 1.0298 square centimeters, the modified architecture reached 29.44% efficiency, with a certified efficiency of 28.85%.
Stability Metrics
Stability tests showed sustained performance across extended storage, thermal, and operational conditions. The optimized devices retained roughly 94% of initial efficiency after more than 3,500 hours of storage. Under continuous operation, cells maintained about 91% efficiency past 750 hours. Thermal exposure tests at 70 °C resulted in 90% efficiency retention after 960 hours.
Lead authors Li Zeng, Wuji Wang, and Liting Tang fabricated and evaluated the tandem cells at Wuhan University. Nature Energy received the manuscript in November 2025 and published the findings on August 5, 2026.
