CH3NH3PbBr3 is not pyroelectric, excluding ferroelectric-enhanced photovoltaic performance

• Main Authors: Yevgeny Rakita, Elena Meirzadeh, Tatyana Bendikov, Vyacheslav Kalchenko, Igor Lubomirsky, Gary Hodes, David Ehre, David Cahen
• Format: Article
• Language: English
• Published: AIP Publishing LLC 2016-05-01
• Series: APL Materials
• Online Access: http://dx.doi.org/10.1063/1.4949760

To experimentally (dis)prove ferroelectric effects on the properties of lead-halide perovskites and of solar cells, based on them, we used second-harmonic-generation spectroscopy and the periodic temperature change (Chynoweth) technique to detect the polar nature of methylammonium lead bromide (MAPbBr3). We find that MAPbBr3 is probably centrosymmetric and definitely non-polar; thus, it cannot be ferroelectric. Whenever pyroelectric-like signals were detected, they could be shown to be due to trapped charges, likely at the interface between the metal electrode and the MAPbBr3 semiconductor. These results indicate that the ferroelectric effects do not affect steady-state performance of MAPbBr3 solar cells.