Researchers from the Ningbo Institute of Materials Technology and Engineering at the Chinese Academy of Sciences recently reported a novel perovskite/silicon tandem solar cell based on flexible ultrathin silicon, with a thickness of about 30 µm.
Despite major progress in the efficiency of rigid perovskite/silicon tandem solar cells, flexible perovskite/silicon tandem solar cells have remained elusive. The team explains that this is due to the challenge of enhancing light absorption in ultrathin silicon bottom cells while maintaining their mechanical flexibility.
In their work, the team demonstrated what it defines as "the first flexible perovskite/silicon tandem solar cell based on ultrathin silicon, approximately 30 µm thick". By reducing wafer thicknesses and adjusting the feature sizes of light-trapping textures, they significantly enhanced the flexibility of the silicon substrate without compromising light utilization. Furthermore, by capping the perovskite top cells, they improved the mechanical durability of the device, addressing concerns related to fractures on the silicon surface.
The resulting flexible perovskite/silicon tandem solar cell achieved a certified stable efficiency of 22.8%, setting a record for flexible solar cells. Additionally, with an exceptional power-to-weight ratio of 3.12 W g−1, the device offers high performance in a lightweight package. Remarkably, the flexible tandems exhibited outstanding bending durability, maintaining 98.2% of their initial performance even after 3,000 bending cycles at a radius of only 1 cm.
This study not only shows that flexible perovskite/silicon tandem solar cells are feasible but also creates new opportunities for lightweight, highly efficient solar cells to be utilized in a variety of applications.
