Vapor breakthrough breaks 30% efficiency barrier for tandem solar cells

Researchers at the National University of Singapore have developed a vapor deposition process to fabricate perovskite-silicon tandem solar cells on industrially relevant textured silicon wafers, achieving efficiencies above 30%. This method overcomes previous challenges related to coating uneven, pyramid-textured silicon surfaces with perovskite layers, which are essential for light trapping but difficult to coat uniformly. By introducing a custom molecular "helper" that bonds to the silicon surface and promotes even perovskite growth, the team created high-quality films that enhance power conversion efficiency and durability. The new tandem cells demonstrated remarkable stability, maintaining over 90% of their output after 1,400 hours at elevated temperatures (85 °C) and showing sustained performance after 2,000 hours under standard solar illumination. This addresses the critical issues of heat sensitivity and long-term degradation that have hindered perovskite solar cells' commercial viability. The researchers aim to scale the technology from small cells to full-size modules and conduct extended