title: Atmospheric influence upon crystallization and electronic disorder and its impact on the photophysical properties of organic-inorganic perovskite solar cells.
abstract: Recently, solution-processable organic-inorganic metal halide perovskites have come to the fore as a result of their high power-conversion efficiencies (PCE) in photovoltaics, exceeding 17%. To attain reproducibility in the performance, one of the critical factors is the processing conditions of the perovskite film, which directly influences the photophysical properties and hence the device performance. Here we study the effect of annealing parameters on the crystal structure of the perovskite films and correlate these changes with its photophysical properties. We find that the crystal formation is kinetically driven by the annealing atmosphere, time and temperature. Annealing in air produces an improved crystallinity and large grain domains as compared to nitrogen. Lower photoluminescence quantum efficiency (PLQE) and shorter photoluminescence (PL) lifetimes are observed for nitrogen annealed perovskite films as compared to the air-annealed counterparts. We note that the limiting nonradiative pathways (i.e., maximizing PLQE) is important for obtaining the highest device efficiency. This indicates a critical impact of the atmosphere upon crystallization and the ultimate device performance.
authors.affiliation: †Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.|‡Cavendish Laboratory, Department of Physics, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Pathak
authors.affiliation: ‡Cavendish Laboratory, Department of Physics, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sepe
authors.affiliation: ‡Cavendish Laboratory, Department of Physics, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Aditya
authors.initials: A
authors.lastname: Sadhanala
authors.affiliation: ‡Cavendish Laboratory, Department of Physics, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Felix
authors.initials: F
authors.lastname: Deschler
authors.affiliation: †Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: Amir
authors.initials: A
authors.lastname: Haghighirad
authors.affiliation: †Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: Nobuya
authors.initials: N
authors.lastname: Sakai
authors.affiliation: ‡Cavendish Laboratory, Department of Physics, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Karl C
authors.initials: KC
authors.lastname: Goedel
authors.affiliation: †Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: Samuel D
authors.initials: SD
authors.lastname: Stranks
authors.affiliation: †Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: Nakita
authors.initials: N
authors.lastname: Noel
authors.affiliation: ‡Cavendish Laboratory, Department of Physics, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Price
authors.affiliation: ‡Cavendish Laboratory, Department of Physics, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Sven
authors.initials: S
authors.lastname: Hüttner
authors.affiliation: §Oxford Silk Group, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Hawkins
authors.affiliation: ‡Cavendish Laboratory, Department of Physics, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Friend
authors.affiliation: ⊥Adolphe Merkle Institute, Chemin des Verdiers, CH-1700, Fribourg, Switzerland.
authors.forename: Ullrich
authors.initials: U
authors.lastname: Steiner
authors.affiliation: †Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Snaith
keywords: crystal symmetry; electronic disorder; organic−inorganic; perovskite solar cell; photovoltaic; thermal annealing