title: Iodine Migration and Degradation of Perovskite Solar Cells Enhanced by Metallic Electrodes.
abstract: We monitored the evolution in time of pinhole-free structures based on FTO/TiO2/CH3NH3PbI2.6Cl0.4layers, with and without spiro-OMeTAD and counter electrodes (Ag, Mo/Ag, and Au), aged at 24 °C in a dark nitrogen atmosphere. In the absence of electrodes, no degradation occurs. While devices with Au show only a 10% drop in power conversion efficiency, remaining stable after a further overheating at 70 °C, >90% is lost when using Ag, with the process being slower for Mo/Ag. We demonstrate that iodine is dislocated by the electric field between the electrodes, and this is an intrinsic cause for electromigration of I-from the perovskite until it reaches the anode. The iodine exhaustion in the perovskite layer is produced when using Ag electrodes, and AgI is formed. We hypothesize that in the presence of Au the iodine migration is limited due to the buildup of I-negative space charge accumulated at the perovskite-OMeTAD interface.
authors.affiliation: National Institute of Materials Physics , 077125 Magurele, Ilfov, Romania.
authors.forename: Cristina
authors.initials: C
authors.lastname: Besleaga
authors.affiliation: National Institute of Materials Physics , 077125 Magurele, Ilfov, Romania.|University of Bucharest , Faculty of Physics, Materials and Devices for Electronics and Optoelectronics Research Center, 077125 Magurele, Ilfov, Romania.
authors.forename: Laura Elena
authors.initials: LE
authors.lastname: Abramiuc
authors.affiliation: National Institute of Materials Physics , 077125 Magurele, Ilfov, Romania.
authors.forename: Viorica
authors.initials: V
authors.lastname: Stancu
authors.affiliation: National Institute of Materials Physics , 077125 Magurele, Ilfov, Romania.
authors.forename: Andrei Gabriel
authors.initials: AG
authors.lastname: Tomulescu
authors.affiliation: National Institute of Materials Physics , 077125 Magurele, Ilfov, Romania.
authors.forename: Marian
authors.initials: M
authors.lastname: Sima
authors.affiliation: National Institute of Materials Physics , 077125 Magurele, Ilfov, Romania.
authors.forename: Liliana
authors.initials: L
authors.lastname: Trinca
authors.affiliation: National Institute of Materials Physics , 077125 Magurele, Ilfov, Romania.
authors.forename: Neculai
authors.initials: N
authors.lastname: Plugaru
authors.affiliation: National Institute of Materials Physics , 077125 Magurele, Ilfov, Romania.
authors.forename: Lucian
authors.initials: L
authors.lastname: Pintilie
authors.affiliation: University of Bucharest , Faculty of Physics, Materials and Devices for Electronics and Optoelectronics Research Center, 077125 Magurele, Ilfov, Romania.
authors.forename: George Alexandru
authors.initials: GA
authors.lastname: Nemnes
authors.affiliation: OPTOELECTRONICA - 2001 S.A., 077125 Magurele, Ilfov, Romania.
authors.forename: Mihaiela
authors.initials: M
authors.lastname: Iliescu
authors.affiliation: School of Science and Engineering, Reykjavik University , Menntavegur 1, IS-101 Reykjavik, Iceland.
authors.forename: Halldor Gudfinnur
authors.initials: HG
authors.lastname: Svavarsson
authors.affiliation: School of Science and Engineering, Reykjavik University , Menntavegur 1, IS-101 Reykjavik, Iceland.
authors.forename: Andrei
authors.initials: A
authors.lastname: Manolescu
authors.affiliation: National Institute of Materials Physics , 077125 Magurele, Ilfov, Romania.
authors.forename: Ioana
authors.identifier: http://orcid.org/0000-0002-3857-8524
authors.initials: I
authors.lastname: Pintilie