Multi-junction all-perovskite tandem solar cells are a promising choice for next-generation solar cells with high efficiency and low fabrication cost. However, the lack of high-quality low-bandgap perovskite absorber layers seriously hampers the development of efficient and stable two-terminal monolithic all-perovskite tandem solar cells. Here, we report a bulk-passivation strategy via incorporation of chlorine, to enlarge grains and reduce electronic disorder in mixed tin–lead low-bandgap (~1.25 eV) perovskite absorber layers. This enables the fabrication of efficient low-bandgap perovskite solar cells using thick absorber layers (~750 nm), which is a requisite for efficient tandem solar cells. Such improvement enables the fabrication of two-terminal all-perovskite tandem solar cells with a champion power conversion efficiency of 21% and steady-state efficiency of 20.7%. The efficiency is retained to 85% of its initial performance after 80 h of operation under continuous illumination.
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The data that support the findings of this study are available from the corresponding authors upon reasonable request.
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The work at University of Toledo is financially supported by the US Department of Energy SunShot Initiative under the Next Generation Photovoltaics 3 programme (DE-FOA-0000990) for perovskite tandem device fabrication, the Office of Naval Research under contract no. N00014-17-1-2223 for device characterization, the Air Force Research Laboratory under the Space Vehicles Directorate (FA9453-11-C-0253) for wide-bandgap perovskite synthesis and the Ohio Research Scholar Program for device modelling and understanding. The work at the National Renewable Energy Laboratory is supported by the US Department of Energy SunShot Initiative under the Next Generation Photovoltaics 3 programme (DE-FOA-0000990) and under contract no. DE-AC36-08-GO28308 with the Alliance for Sustainable Energy, the Manager and Operator of the National Renewable Energy Laboratory.
The authors declare no competing interests.
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Zhao, D., Chen, C., Wang, C. et al. Efficient two-terminal all-perovskite tandem solar cells enabled by high-quality low-bandgap absorber layers. Nat Energy 3, 1093–1100 (2018). https://doi.org/10.1038/s41560-018-0278-x
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