Perovskite triple-junction solar cells move closer to ultra-high efficiency

A team from Shanghai Jiao Tong University has published a wide-ranging review of perovskite/perovskite/silicon triple-junction solar cells (PSTJSCs), highlighting their rapid progress and outlining future research priorities. The study, appearing in Nano-Micro Letters, was led by Leiping Duan, Cheng Xu, and Jianghui Zheng.

As silicon solar cells approach their theoretical ceiling of 29.4 percent efficiency, researchers are turning to multi-junction devices. Perovskite-based tandems have drawn particular interest because of their tunable bandgaps, cost-effective processing, and strong optoelectronic performance.

Triple-junction designs promise significant gains. Modeling indicates that optimized structures could achieve efficiencies beyond 49 percent, far surpassing current perovskite/silicon tandems. Since the first proof-of-concept PSTJSC in 2018 achieved only 14 percent efficiency, certified devices now exceed 27 percent as of 2024.

Challenges remain, including current mismatch between subcells, voltage deficits in wide-bandgap perovskites caused by defects and interfaces, light-induced phase segregation in mixed-halide absorbers, and overall device stability under long-term stress.

The review highlights strategies under investigation. These include fine-tuning bandgaps with halide and cation engineering, incorporating tin-based perovskites, and using transparent conductive oxides or ultrathin metals for efficient interconnections. Stability research is also intensifying, with additive engineering, improved crystallinity, and advanced encapsulation methods under development.

Future progress will depend on combining molecular-level materials design with robust device architectures. The authors stress the need for scalable fabrication techniques compatible with textured silicon and encapsulation systems that ensure decades of durability. With these advances, PSTJSCs could deliver affordable, sustainable, and ultra-efficient solar power at commercial scale.

Research Report:Monolithic Perovskite/Perovskite/Silicon Triple-Junction Solar Cells: Fundamentals, Progress, and Prospects