NUS researchers developed a perovskite–organic tandem solar cell with a record 26.4% efficiency on 1 cm²—the highest for its kind—thanks to a new narrow-bandgap organic absorber that greatly enhances NIR light capture.
The breakthrough was led by Asst. Prof. Hou Yi from NUS’s College of Design and Engineering. He also heads the Perovskite-based Multijunction Solar Cells Group at the Solar Energy Research Institute of Singapore (SERIS) at NUS.
Realizing the Potential of Tandem Solar Cells
Perovskite and organic semiconductors feature highly tunable bandgaps, allowing tandem cells to reach near-theoretical efficiency limits. “Because they’re lightweight and flexible, perovskite–organic tandem solar cells are perfect for powering on-device applications like drones, wearables, smart fabrics, and AI-powered tech,” said Asst. Prof. Hou.
However, inefficient NIR absorbers have limited perovskite–organic tandem cell performance compared to other designs.
Tapping Into Near-Infrared Energy
To tackle this challenge, Asst. Prof. Hou and his team engineered an asymmetric organic acceptor featuring an extended conjugated structure. This design enables deep near-infrared (NIR) light absorption while ensuring strong charge separation and orderly molecular packing. Ultrafast spectroscopy and device physics analyses confirmed efficient charge carrier collection with minimal energy loss.
The team then combined this high-performing organic subcell with a top-layer perovskite cell, using a transparent conducting oxide (TCO) interlayer to connect the two.
The resulting tandem cell reached a power conversion efficiency of 27.5% on 0.05 cm² samples and 26.7% on 1 cm² devices, with the 26.4% figure independently verified—setting a new certified benchmark for perovskite–organic, perovskite–CIGS, and single-junction perovskite cells of similar size.
“With efficiencies on track to surpass 30%, these flexible films are perfect for roll-to-roll manufacturing and applications on curved or textile surfaces—imagine self-powered health patches or smart fabrics that track biometrics without bulky batteries,” said Asst. Prof. Hou.
Looking ahead, the NUS team aims to boost real-world stability and transition to pilot-scale manufacturing, key steps toward commercializing flexible, high-efficiency solar solutions.
Read the original article on: Tech Xplore
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