Issue 8, 2019

Ferroelectricity-free lead halide perovskites

Abstract

Direct piezoelectric force microscopy (DPFM) is employed to examine whether or not lead halide perovskites exhibit ferroelectricity. Compared to conventional piezoelectric force microscopy, DPFM is a novel technique capable of measuring piezoelectricity directly. This fact is fundamental to be able to examine the existence of ferroelectricity in lead halide perovskites, an issue that has been under debate for several years. DPFM is used to detect the current signals, i.e. changes in the charge distribution under the influence of the scan direction and applied force of the atomic force microscope (AFM) tip in contact mode. For comparison, (i) we use DPFM on lead halide perovskites and well-known ferroelectric materials (i.e. periodically poled lithium niobate and lead zirconate titanate); and (ii) we conduct parallel experiments on MAPbI3 films of different grain sizes, film thicknesses, substrates, and textures using DPFM as well as piezoelectric force microscopy (PFM) and electrostatic force microscopy (EFM). In contrast to previous work that claimed there were ferroelectric domains in MAPbI3 perovskite films, our work shows that the studied perovskite films Cs0.05(FA0.83MA0.17)0.95Pb(I0.83Br0.17)3 and MAPbI3 are ferroelectricity-free. The observed current profiles of lead halide perovskites possibly originate from ion migration that happens under an applied electrical bias and in strained samples under mechanical stress. This work provides a deeper understanding of the fundamental physical properties of the organic–inorganic lead halide perovskites and solves a longstanding dispute about their non-ferroelectric character: an issue of high relevance for optoelectronic and photovoltaic applications.

Graphical abstract: Ferroelectricity-free lead halide perovskites

Associated articles

Supplementary files

Article information

Article type
Paper
Submitted
18 Mar 2019
Accepted
21 Jun 2019
First published
21 Jun 2019
This article is Open Access
Creative Commons BY license

Energy Environ. Sci., 2019,12, 2537-2547

Ferroelectricity-free lead halide perovskites

A. Gómez, Q. Wang, A. R. Goñi, M. Campoy-Quiles and A. Abate, Energy Environ. Sci., 2019, 12, 2537 DOI: 10.1039/C9EE00884E

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