The existence and impact of persistent ferroelectric domains in MAPbI 3

Date Published
01/2019
Publication Type
Journal Article
Authors
DOI
10.1126/sciadv.aas9311
Abstract

Methylammonium lead iodide (MAPbI3) exhibits exceptional photovoltaic performance, but there remains substantial controversy over the existence and impact of ferroelectricity on the photovoltaic response. We confirm ferroelectricity in MAPbI3 single crystals and demonstrate mediation of the electronic response by ferroelectric domain engineering. The ferroelectric response sharply declines above 57°C, consistent with the tetragonal-to-cubic phase transition. Concurrent band excitation piezoresponse force microscopy–contact Kelvin probe force microscopy shows that the measured response is not dominated by spurious electrostatic interactions. Large signal poling (>16 V/cm) orients the permanent polarization into large domains, which show stabilization over weeks. X-ray photoemission spectroscopy results indicate a shift of 400 meV in the binding energy of the iodine core level peaks upon poling, which is reflected in the carrier concentration results from scanning microwave impedance microscopy. The ability to control the ferroelectric response provides routes to increase device stability and photovoltaic performance through domain engineering.

Journal
Science Advances
Volume
5
Year of Publication
2019
Issue
1
Pagination
eaas9311
Short Title
Sci. Adv.
Refereed Designation
Refereed
Organizations
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