title: Photoinduced Stark Effects and Mechanism of Ion Displacement in Perovskite Solar Cell Materials.
abstract: Organometallic halide perovskites (OMHPs) have recently emerged as a promising class of materials in photovoltaic technology. Here, we present an in-depth investigation of the physics in these systems by measuring the photoinduced absorption (PIA) in OMHPs as a function of materials composition, excitation wavelength, and modulation frequency. We report a photoinduced Stark effect that depends on the excitation wavelength and on the dipole strength of the monovalent cations in the A position of the ABX3perovskite. The results presented are corroborated by density functional theory calculations and provide fundamental information about the photoinduced local electric field change under blue and red excitation as well as insights into the mechanism of light-induced ion displacement in OMHPs. For optimized perovskite solar cell devices beyond 19% efficiency, we show that excess thermalization energy of blue photons plays a role in overcoming the activation energy for ion diffusion.
authors.affiliation: Department of Chemistry - Ångström Laboratory, Physical Chemistry, Uppsala University , Box 523, SE 75120 Uppsala, Sweden.|Department of Chemistry - Ångström Laboratory, Structural Chemistry, Uppsala University , Box 538, SE 75120 Uppsala, Sweden.
authors.forename: Meysam
authors.identifier: 0000-0001-6776-5460
authors.initials: M
authors.lastname: Pazoki
authors.affiliation: Laboratory of Photomolecular Science, Department of Chemistry and Chemical Engineering, Swiss Federal Institute of Technology , Station 6, CH-1015 Lausanne, Switzerland.
authors.forename: T Jesper
authors.identifier: 0000-0002-4317-2879
authors.initials: TJ
authors.lastname: Jacobsson
authors.affiliation: Department of Chemistry - Ångström Laboratory, Structural Chemistry, Uppsala University , Box 538, SE 75120 Uppsala, Sweden.
authors.forename: Jolla
authors.identifier: 0000-0003-3570-0050
authors.initials: J
authors.lastname: Kullgren
authors.affiliation: Department of Chemistry - Ångström Laboratory, Physical Chemistry, Uppsala University , Box 523, SE 75120 Uppsala, Sweden.
authors.forename: Erik M J
authors.identifier: 0000-0001-9358-8277
authors.initials: EM
authors.lastname: Johansson
authors.affiliation: Laboratory of Photomolecular Science, Department of Chemistry and Chemical Engineering, Swiss Federal Institute of Technology , Station 6, CH-1015 Lausanne, Switzerland.
authors.forename: Anders
authors.initials: A
authors.lastname: Hagfeldt
authors.affiliation: Department of Chemistry - Ångström Laboratory, Physical Chemistry, Uppsala University , Box 523, SE 75120 Uppsala, Sweden.
authors.forename: Gerrit
authors.identifier: 0000-0002-8249-1469
authors.initials: G
authors.lastname: Boschloo
authors.affiliation: Department of Engineering Sciences, Solid State Physics, Uppsala University , Box 534, SE 751 21 Uppsala, Sweden.
authors.forename: Tomas
authors.identifier: 0000-0003-2759-7356
authors.initials: T
authors.lastname: Edvinsson
keywords: CH3NH3PbI3; Stark effect; cation-dependent ion movement; mixed halide perovskites; perovskite solar cells; photoinduced ion migration