The dynamics of methylammonium ions in hybrid organic-inorganic perovskite solar cells
Author(s)
Type
Journal Article
Abstract
Methylammonium lead iodide perovskite can make high-efficiency solar cells, which also show an unexplained photocurrent hysteresis dependent on the device-poling history. Here we report quasielastic neutron scattering measurements showing that dipolar CH3NH3+ ions reorientate between the faces, corners or edges of the pseudo-cubic lattice cages in CH3NH3PbI3 crystals with a room temperature residence time of ~14 ps. Free rotation, π-flips and ionic diffusion are ruled out within a 1–200-ps time window. Monte Carlo simulations of interacting CH3NH3+ dipoles realigning within a 3D lattice suggest that the scattering measurements may be explained by the stabilization of CH3NH3+ in either antiferroelectric or ferroelectric domains. Collective realignment of CH3NH3+ to screen a device’s built-in potential could reduce photovoltaic performance. However, we estimate the timescale for a domain wall to traverse a typical device to be ~0.1–1 ms, faster than most observed hysteresis.
Date Issued
2015-05-29
Date Acceptance
2015-04-07
ISSN
2041-1723
Publisher
Nature Publishing Group
Journal / Book Title
Nature Communications
Volume
6
Issue
4
Copyright Statement
© 2015, Rights Managed by Nature Publishing Group. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Grant Number
EP/J002305/1
EP/J021199/1
Subjects
Science & Technology
Multidisciplinary Sciences
Science & Technology - Other Topics
ORGANOMETAL HALIDE PEROVSKITES
INCOHERENT-SCATTERING LAW
METHYL-GROUP DYNAMICS
NEUTRON-SCATTERING
PHASE-TRANSITIONS
V HYSTERESIS
THIN-FILMS
CH3NH3PBI3
DIFFUSION
OXIDES
Science & Technology
Multidisciplinary Sciences
Science & Technology - Other Topics
INCOHERENT-SCATTERING LAW
METHYL-GROUP DYNAMICS
NEUTRON-SCATTERING
PHASE-TRANSITIONS
HYSTERESIS
DIFFUSION
OXIDES
PERFORMANCE
SEPARATION
ROTATION
Publication Status
Published
Article Number
ARTN 7124