The Influence of Water Vapor on the Stability and Processing of Hybrid Perovskite Solar Cells Made from Non-Stoichiometric Precursor Mixtures.
We investigated the influence of moisture on methylammonium lead iodide perovskite (MAPbI3) films and solar cells derived from non-stoichiometric precursor mixtures. We followed both the structural changes under controlled air humidity through in situ X-ray diffraction, and the electronic behavior of devices prepared from these films. A small PbI2excess in the films improved the stability of the perovskite compared to stoichiometric samples. We assign this to excess PbI2layers at the perovskite grain boundaries or to the termination of the perovskite crystals with Pb and I. In contrast, the MAI-excess films composed of smaller perovskite crystals showed increased electronic disorder and reduced device performance owing to poor charge collection. Upon exposure to moisture followed by dehydration (so-called solvent annealing), these films recrystallized to form larger, highly oriented crystals with fewer electronic defects and a remarkable improvement in photocurrent and photovoltaic efficiency.
Department of Chemistry, LMU Munich, 81377, Munich, Germany.
Michiel L
ML
Petrus
Department of Chemistry, LMU Munich, 81377, Munich, Germany.
Yinghong
Y
Hu
Physics Department, Imperial College London, London, SW7 2AZ, United Kingdom.
Davide
D
Moia
Physics Department, Imperial College London, London, SW7 2AZ, United Kingdom.
Philip
P
Calado
Physics Department, Imperial College London, London, SW7 2AZ, United Kingdom.
Aurélien M A
AM
Leguy
Physics Department, Imperial College London, London, SW7 2AZ, United Kingdom. piers.barnes@imperial.ac.uk.
Piers R F
PR
Barnes
Department of Chemistry, LMU Munich, 81377, Munich, Germany. pablo.docampo@cup.lmu.de.
Pablo
P
Docampo
D000578:Amidines / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry*; D004355:Drug Stability; D011211:Electric Power Supplies; D010087:Oxides / Q000737:chemistry*; D012993:Solar Energy; D012997:Solvents / Q000737:chemistry; D013227:Steam; D014025:Titanium / Q000737:chemistry*
D000578:Amidines; D017610:Calcium Compounds; D010087:Oxides; D012997:Solvents; D013227:Steam; C059910:perovskite; C077922:formamidine; D014025:Titanium
non-stoichiometric; perovskite; solar cells; stability; water vapor