Flexible solar cells based on foldable silicon wafers with blunted edges

WZ Liu and YJ Liu and ZQ Yang and CQ Xu and XD Li and SL Huang and JH Shi and JL Du and AJ Han and YH Yang and GN Xu and J Yu and JJ Ling and J Peng and LP Yu and B Ding and Y Gao and K Jiang and ZF Li and YC Yang and ZJ Li and SH Lan and HX Fu and B Fan and YY Fu and W He and FR Li and X Song and YN Zhou and Q Shi and GY Wang and L Guo and JX Kang and XB Yang and DD Li and ZC Wang and J Li and S Thoroddsen and R Cai and FH Wei and GQ Xing and Y Xie and XC Liu and LP Zhang and FY Meng and ZF Di and ZX Liu, NATURE, 617, 717-+ (2023).

DOI: 10.1038/s41586-023-05921-z

Flexible solar cells have a lot of market potential for application in photovoltaics integrated into buildings and wearable electronics because they are lightweight, shockproof and self-powered. Silicon solar cells have been successfully used in large power plants. However, despite the efforts made for more than 50 years, there has been no notable progress in the development of flexible silicon solar cells because of their rigidity1-4. Here we provide a strategy for fabricating large-scale, foldable silicon wafers and manufacturing flexible solar cells. A textured crystalline silicon wafer always starts to crack at the sharp channels between surface pyramids in the marginal region of the wafer. This fact enabled us to improve the flexibility of silicon wafers by blunting the pyramidal structure in the marginal regions. This edge- blunting technique enables commercial production of large-scale (>240 cm(2)), high-effliciency (>24%) silicon solar cells that can be rolled similarly to a sheet of paper. The cells retain 100% of their power conversion efficiency after 1,000 side-to-side bending cycles. After being assembled into large (>10,000 cm(2)) flexible modules, these cells retain 99.62% of their power after thermal cycling between -70 degrees C and 85 degrees C for 120 h. Furthermore, they retain 96.03% of their power after 20 min of exposure to air flow when attached to a soft gasbag, which models wind blowing during a violent storm.

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