title: Effect of Halide Composition on the Photochemical Stability of Perovskite Photovoltaic Materials.
abstract: The photochemical stability of encapsulated films of mixed halide perovskites with a range of MAPb(I1-xBrx)3(MA=methylammonium) compositions (solid solutions) was investigated under accelerated stressing using concentrated sunlight. The relevance of accelerated testing to standard operational conditions of solar cells was confirmed by comparison to degradation experiments under outdoor sunlight exposure. We found that MAPbBr3films exhibited no degradation, while MAPbI3and mixed halide MAPb(I1-xBrx)3films decomposed yielding crystallization of inorganic PbI2accompanied by degradation of the perovskite solar light absorption, with faster absorption degradation in mixed halide films. The crystal coherence length was found to correlate with the stability of the films. We postulate that the introduction of Br into the mixed halide solid solution stressed its structure and induced more structural defects and/or grain boundaries compared to pure halide perovskites, which might be responsible for the accelerated degradation. Hence, the cause for accelerated degradation may be the increased defect density rather than the chemical composition of the perovskite materials.
authors.affiliation: Dept. of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Midreshet Sede Boqer, 8499000, Israel.|Casali Center for Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.
authors.forename: Ravi K
authors.initials: RK
authors.lastname: Misra
authors.affiliation: Dept. of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Midreshet Sede Boqer, 8499000, Israel.
authors.forename: Laura
authors.initials: L
authors.lastname: Ciammaruchi
authors.affiliation: Casali Center for Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.
authors.forename: Sigalit
authors.initials: S
authors.lastname: Aharon
authors.affiliation: Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Be'er Sheva, 8410501, Israel.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Mogilyansky
authors.affiliation: Casali Center for Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.
authors.forename: Lioz
authors.initials: L
authors.lastname: Etgar
authors.affiliation: Dept. of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Midreshet Sede Boqer, 8499000, Israel. irisvf@bgu.ac.il.|Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Be'er Sheva, 8410501, Israel. irisvf@bgu.ac.il.
authors.forename: Iris
authors.initials: I
authors.lastname: Visoly-Fisher
authors.affiliation: Dept. of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Midreshet Sede Boqer, 8499000, Israel. keugene@bgu.ac.il.|Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Be'er Sheva, 8410501, Israel. keugene@bgu.ac.il.
authors.forename: Eugene A
authors.initials: EA
authors.lastname: Katz
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry*; D004355:Drug Stability; D011211:Electric Power Supplies; D006219:Halogens / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D013472:Sunlight; D014025:Titanium / Q000737:chemistry*
chemical_list: D017610:Calcium Compounds; D006219:Halogens; D010087:Oxides; C059910:perovskite; D014025:Titanium
keywords: mixed halide perovskites; organic-inorganic hybrid composites; photolysis; photovoltaics; stability