Journal Article

Perovskite-perovskite tandem photovoltaics with optimized band gaps

Milot, Rebecca L., Moghadam, Farhad, Palmstrom, Axel, Eperon, Giles E., Conings, Bert, Ma, Wen, Leijtens, Tomas, Volonakis, George, Snaith, Henry J., Babayigit, Aslihan, Patel, Jay B., Herz, Laura M., McMeekin, David P., Giustino, Feliciano, Sutton, Rebecca J., Belisle, Rebecca A., Slotcavage, Daniel J., Bent, Stacey, Prasanna, Rohit, Green, Thomas, Wang, Jacob Tse-Wei, Parrott, Elizabeth S., McGehee, Michael D., Johnston, Michael B., May, Richard, Boyen, Hans-Gerd, Bush, Kevin A.

2016

Overview

We demonstrate four- and two-terminal perovskite-perovskite tandem solar cells with ideally matched band gaps. We develop an infrared-absorbing 1.2-electron volt band-gap perovskite, FA0.75Cs0.25Sn0.5Pb0.5I₃, that can deliver 14.8% efficiency. By combining this material with a wider-band gap FA0.83Cs0.17Pb(I0.5Br0.5)₃ material, we achieve monolithic two-terminal tandem efficiencies of 17.0% with >1.65-volt open-circuit voltage. We also make mechanically stacked four-terminal tandem cells and obtain 20.3% efficiency. Notably, we find that our infrared-absorbing perovskite cells exhibit excellent thermal and atmospheric stability, not previously achieved for Sn-based perovskites. This device architecture and materials set will enable \"all-perovskite\" thin-film solar cells to reach the highest efficiencies in the long term at the lowest costs.

• Publisher: American Association for the Advancement of Science,The American Association for the Advancement of Science
• Subject: Band gap / Efficiency / Energy gaps (solid state) / Fabrication / Optimization techniques / Perovskite / Perovskites / Photovoltaic cells / Photovoltaics / Solar cells / Thin films / Voltage / Wavelengths