Silicon solar cells are approaching their theoretical efficiency limit of 29%. This limitation can be exceeded with advanced device architectures, where two or more solar cells are stacked to improve the harvesting of solar energy. In this work, we devise a tandem device with a perovskite layer conformally coated on a silicon bottom cell featuring micrometric pyramids—the industry standard—to improve its photocurrent. Using an additive in the processing sequence, we regulate the perovskite crystallization process and alleviate recombination losses occurring at the perovskite top surface interfacing the electron-selective contact [buckminsterfullerene (C 60 )]. We demonstrate a device with an active area of 1.17 square centimeters, reaching a certified power conversion efficiency of 31.25%.

High control chemical vapour deposition of (Cs,FA)PbI3 perovskite provides insights into CVD kinetics and perovskite phase evolution.

The migration of mobile ions has long been considered a source of performance degradation in devices based on halide perovskites, but details regarding the mechanisms and extent of this problem...

Tin fluoride (SnF 2 ) is an indispensable additive for high-efficiency Pb-Sn perovskite solar cells (PSCs). However, the spatial distribution of SnF 2 in the perovskite absorber is seldom investigated while essential for a comprehensive understanding of the exact role of the SnF 2 additive. Herein, we revealed the spatial distribution of the SnF 2 additive and made structure-optoelectronic properties-flexible photovoltaic performance correlation. We observed the chemical transformation of SnF 2 to a fluorinated oxyphase on the Pb-Sn perovskite film surface due to its rapid oxidation. In addition, at the buried perovskite interface, we detected and visualized the accumulation of F − ions. We found that the photoluminescence quantum yield of Pb-Sn perovskite reached the highest value with 10 mol % SnF 2 in the precursor solution. When integrating the optimized absorber in flexible devices, we obtained the flexible Pb-Sn perovskite narrow bandgap (1.24 eV) solar cells with an efficiency of 18.5% and demonstrated 23.1% efficient flexible four-terminal all-perovskite tandem cells.

Perovskite‐Cu(In,Ga)Se2 (CIGS) thin‐film tandem technology provides an exciting prospect to achieve low‐cost high‐efficiency photovoltaic devices by high throughput roll‐to‐roll processing on flexible substrates. However, no report on flexible perovskite‐CIGS mini‐modules has been published due to scribing‐related challenges in realizing near‐infrared (NIR)‐transparent perovskite mini‐modules on flexible substrates. Herein, an NIR‐transparent flexible perovskite mini‐module with an efficiency of 10.8% and an NIR‐transparency of over 75% is reported. All‐laser scribed interconnection approach is used to realize monolithic interconnection of mini‐modules on thermally sensitive soft flexible substrate. An analytical method is utilized to optimize the mini‐module layout and achieve a geometric fill factor of over 93%. Further, as a proof of concept, a flexible perovskite‐CIGS tandem mini‐module with an efficiency of 18.4% on an aperture area of 2.03 cm2 is demonstrated. To conclude, pathways for improving the efficiency of flexible NIR‐transparent perovskite mini‐modules are discussed.