Low-bandgap mixed tin–lead iodide perovskite absorbers with long carrier lifetimes for all-perovskite tandem solar cells


Tandem solar cells using only metal-halide perovskite sub-cells are an attractive choice for next-generation solar cells. However, the progress in developing efficient all-perovskite tandem solar cells has been hindered by the lack of high-performance low-bandgap perovskite solar cells. Here, we report efficient mixed tin–lead iodide low-bandgap (1.25 eV) perovskite solar cells with open-circuit voltages up to 0.85 V and over 70% external quantum efficiencies in the infrared wavelength range of 700–900 nm, delivering a short-circuit current density of over 29 mA cm−2 and demonstrating suitability for bottom-cell applications in all-perovskite tandem solar cells. Our low-bandgap perovskite solar cells achieve a maximum power conversion efficiency of 17.6% and a certified efficiency of 17.01% with a negligible current–voltage hysteresis. When mechanically stacked with a 1.58 eV bandgap perovskite top cell, our best all-perovskite 4-terminal tandem solar cell shows a steady-state efficiency of 21.0%.

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Figure 1: Device architecture schematic and performance.
Figure 2: Characterization of (FASnI3)0.6(MAPbI3)0.4 perovskite films.
Figure 3: EQE spectra of (FASnI3)0.6(MAPbI3)0.4 PVSCs.
Figure 4: Characterization of the all-perovskite 4-terminal tandem cell.


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This work is financially supported by the US Department of Energy (DOE) SunShot Initiative under the Next Generation Photovoltaics 3 programme (DE-FOA-0000990), National Science Foundation under contract no. CHE-1230246 and DMR-1534686, and the Ohio Research Scholar Program. 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) under contract no. DE-AC36-08-GO28308. This research used the resources of the Ohio Supercomputer Center and the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the US Department of Energy under contract no. DE-AC02-05CH11231. The work at Southeast University (P.R. China) is supported by National Natural Science Foundation of China (NSFC) under contract no. 91422301.

Author information




D.Z. and Y.Yan conceived the project. D.Z. carried out film and device fabrication and characterization. Y.Yu and C.W. prepared wide-bandgap perovskite film and devices. Y.Yu assisted with SEM measurement. W.L. assisted in device fabrication and characterization. C.R.G., A.J.C. and L.G. helped with the characterization. N.S. and R.J.E. conducted TRPL measurements. D.Z. and Y.Yan analysed the data and wrote the manuscript. K.Z. and R.-G.X. helped with the manuscript preparation. All the authors discussed the results and commented on the manuscript. Y.Yan supervised the project.

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Correspondence to Dewei Zhao or Yanfa Yan.

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The authors declare no competing financial interests.

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Supplementary Figure 19, Supplementary Tables 13, Supplementary Methods, Supplementary References. (PDF 2434 kb)

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Zhao, D., Yu, Y., Wang, C. et al. Low-bandgap mixed tin–lead iodide perovskite absorbers with long carrier lifetimes for all-perovskite tandem solar cells. Nat Energy 2, 17018 (2017). https://doi.org/10.1038/nenergy.2017.18

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