title: Using Low Temperature Photoluminescence Spectroscopy to Investigate CH₃NH₃PbI₃ Hybrid Perovskite Degradation.
abstract: Investigating the stability and evaluating the quality of the CH₃NH₃PbI₃ perovskite structures is quite critical both to the design and fabrication of high-performance perovskite devices and to fundamental studies of the photophysics of the excitons. In particular, it is known that, under ambient conditions, CH₃NH₃PbI₃ degrades producing some PbI₂. We show here that low temperature Photoluminescence (PL) spectroscopy is a powerful tool to detect PbI₂ traces in hybrid perovskite layers and single crystals. Because PL spectroscopy is a signal detection method on a black background, small PbI₂ traces can be detected, when other methods currently used at room temperature fail. Our study highlights the extremely high stability of the single crystals compared to the thin layers and defects and grain boundaries are thought to play an important role in the degradation mechanism.
authors.affiliation: Laboratoire Aim&#233; Cotton, Ecole Normale Sup&#233;rieure de Cachan, CNRS, Universit&#233; Paris-Sud, Universit&#233; Paris-Saclay, B&#226;t 505 Campus d'Orsay, 91405 Orsay, France. kjemli@ens-cachan.fr.|Laboratoire de Photophysique et Photochimie Supramol&#233;culaires et Macromol&#233;culaires de l'Ecole Normale Sup&#233;rieure de Cachan, 61 Avenue du Pr&#233;sident Wilson, 94235 Cachan, France. kjemli@ens-cachan.fr.
authors.forename: Khaoula
authors.initials: K
authors.lastname: Jemli
authors.affiliation: Laboratoire Aim&#233; Cotton, Ecole Normale Sup&#233;rieure de Cachan, CNRS, Universit&#233; Paris-Sud, Universit&#233; Paris-Saclay, B&#226;t 505 Campus d'Orsay, 91405 Orsay, France. hiba.diab@ens-cachan.fr.
authors.forename: Hiba
authors.initials: H
authors.lastname: Diab
authors.affiliation: Laboratoire Aim&#233; Cotton, Ecole Normale Sup&#233;rieure de Cachan, CNRS, Universit&#233; Paris-Sud, Universit&#233; Paris-Saclay, B&#226;t 505 Campus d'Orsay, 91405 Orsay, France. ferdinand.ledee@ens-cachan.fr.|Laboratoire de Photophysique et Photochimie Supramol&#233;culaires et Macromol&#233;culaires de l'Ecole Normale Sup&#233;rieure de Cachan, 61 Avenue du Pr&#233;sident Wilson, 94235 Cachan, France. ferdinand.ledee@ens-cachan.fr.
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Lédée
authors.affiliation: Laboratoire Aim&#233; Cotton, Ecole Normale Sup&#233;rieure de Cachan, CNRS, Universit&#233; Paris-Sud, Universit&#233; Paris-Saclay, B&#226;t 505 Campus d'Orsay, 91405 Orsay, France. gaelle.allard@ens-cachan.fr.
authors.forename: Gaelle
authors.initials: G
authors.lastname: Trippé-Allard
authors.affiliation: Groupe d'Etudes de la Mati&#232;re Condens&#233;e (GEMaC), CNRS, Universit&#233; de Versailles Saint-Quentin-en-Yvelines, Universit&#233; Paris-Saclay, 45 Avenue des Etats-Unis, 78035 Versailles Cedex, France. damien.garrot@uvsq.fr.
authors.forename: Damien
authors.initials: D
authors.lastname: Garrot
authors.affiliation: Laboratory of Innovation in Surface Chemistry and Nanosciences, NIMBE, CEA, CNRS, Universit&#233; Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France. bernard.geffroy@polytechnique.edu.
authors.forename: Bernard
authors.initials: B
authors.lastname: Geffroy
authors.affiliation: Laboratoire Aim&#233; Cotton, Ecole Normale Sup&#233;rieure de Cachan, CNRS, Universit&#233; Paris-Sud, Universit&#233; Paris-Saclay, B&#226;t 505 Campus d'Orsay, 91405 Orsay, France. jean-sebastien.lauret@lac.u-psud.fr.
authors.forename: Jean-Sébastien
authors.initials: JS
authors.lastname: Lauret
authors.affiliation: Laboratoire de Photophysique et Photochimie Supramol&#233;culaires et Macromol&#233;culaires de l'Ecole Normale Sup&#233;rieure de Cachan, 61 Avenue du Pr&#233;sident Wilson, 94235 Cachan, France. Pierre.Audebert@ppsm.ens-cachan.fr.
authors.forename: Pierre
authors.initials: P
authors.lastname: Audebert
authors.affiliation: Laboratoire Aim&#233; Cotton, Ecole Normale Sup&#233;rieure de Cachan, CNRS, Universit&#233; Paris-Sud, Universit&#233; Paris-Saclay, B&#226;t 505 Campus d'Orsay, 91405 Orsay, France. emmanuelle.deleporte@ens-cachan.fr.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Deleporte
mesh_terms: D017610:Calcium Compounds / Q000032:analysis* / Q000737:chemistry; D003080:Cold Temperature; D049449:Luminescence; D008163:Luminescent Measurements; D010087:Oxides / Q000032:analysis* / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods*; D014025:Titanium / Q000032:analysis* / Q000737:chemistry
chemical_list: D017610:Calcium Compounds; D010087:Oxides; C059910:perovskite; D014025:Titanium
keywords: CH3NH3PbI3; degradation; hybrid perovskite; optoelectronics; photoluminescence; solar cells