title: Perovskite-perovskite tandem photovoltaics with optimized band gaps.
abstract: 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)3material, 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.
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.|Department of Chemistry, University of Washington, Seattle, WA, USA.
authors.forename: Giles E
authors.initials: GE
authors.lastname: Eperon
authors.affiliation: Department of Materials Science, Stanford University, Lomita Mall, Stanford, CA, USA.
authors.forename: Tomas
authors.initials: T
authors.lastname: Leijtens
authors.affiliation: Department of Materials Science, Stanford University, Lomita Mall, Stanford, CA, USA.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Bush
authors.affiliation: Department of Materials Science, Stanford University, Lomita Mall, Stanford, CA, USA.
authors.forename: Rohit
authors.initials: R
authors.lastname: Prasanna
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Green
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Jacob Tse-Wei
authors.initials: JT
authors.lastname: Wang
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.
authors.forename: David P
authors.initials: DP
authors.lastname: McMeekin
authors.affiliation: Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK.
authors.forename: George
authors.initials: G
authors.lastname: Volonakis
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Milot
authors.affiliation: Department of Chemistry, University of Washington, Seattle, WA, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: May
authors.affiliation: Department of Chemical Engineering, Stanford University, Via Ortega, Stanford, CA, USA.
authors.forename: Axel
authors.initials: A
authors.lastname: Palmstrom
authors.affiliation: Department of Materials Science, Stanford University, Lomita Mall, Stanford, CA, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Slotcavage
authors.affiliation: Department of Materials Science, Stanford University, Lomita Mall, Stanford, CA, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Belisle
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Jay B
authors.initials: JB
authors.lastname: Patel
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Parrott
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Sutton
authors.affiliation: SunPreme, Palomar Avenue, Sunnyvale, CA, USA.
authors.forename: Wen
authors.initials: W
authors.lastname: Ma
authors.affiliation: SunPreme, Palomar Avenue, Sunnyvale, CA, USA.
authors.forename: Farhad
authors.initials: F
authors.lastname: Moghadam
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.|Institute for Materials Research, Hasselt University, Diepenbeek, Belgium.
authors.forename: Bert
authors.initials: B
authors.lastname: Conings
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.|Institute for Materials Research, Hasselt University, Diepenbeek, Belgium.
authors.forename: Aslihan
authors.initials: A
authors.lastname: Babayigit
authors.affiliation: Institute for Materials Research, Hasselt University, Diepenbeek, Belgium.
authors.forename: Hans-Gerd
authors.initials: HG
authors.lastname: Boyen
authors.affiliation: Department of Chemical Engineering, Stanford University, Via Ortega, Stanford, CA, USA.
authors.forename: Stacey
authors.initials: S
authors.lastname: Bent
authors.affiliation: Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK.
authors.forename: Feliciano
authors.initials: F
authors.lastname: Giustino
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Herz
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Johnston
authors.affiliation: Department of Chemistry, University of Washington, Seattle, WA, USA. mmcgehee@stanford.edu henry.snaith@physics.ox.ac.uk.
authors.forename: Michael D
authors.initials: MD
authors.lastname: McGehee
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK. mmcgehee@stanford.edu henry.snaith@physics.ox.ac.uk.
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Snaith