Apparent ferroelectric-like and dielectric properties of CH₃NH₃PbI₃ synthesized in ambient air

Abstract

CH₃NH₃PbI₃ (MAPbI₃) has attracted great interest of researchers for its impressively high efficiency in solar cells. Researchers have debated whether or not MAPbI₃ is ferroelectric for a long time. In this work, the ferroelectric hysteresis loops, dielectric properties, the real part of impedance and domain structure of the samples synthesized in ambient air (not in a glove box) are investigated. No domain switching current is found in the pellets and films at room temperature, but ferroelectric domains are observed in the films with in plane and out of plane conurations. The dielectric constant as a function of temperature shows that there is no ferroelectric to paraelectric phase transition. The complexity and uncertainty concerning the ferroelectricity of the samples synthesized in ambient air are the same as those synthesized in a glove box.

Keywords:

• Halid perovskite
• ferroelectric hysteresis loops
• domain
• dielectric properties

Additional information

Funding

This research work was supported by the National Key R&D Program of China (No. 2016YFB0402701, 2016YFA0201103), the National Basic Research Program of China under Grant (No. 2015CB654605), the National Nature Science Foundation of China (Nos. 51672293, 11475240), the Instrument Developing Project of Chinese Academy of Sciences (No. ZDKYYQ20180004), the Chinese Academy of Sciences President’s International Fellowship Initiative, Grant/Award Number: 2017VMA0018 and 2011T2G03, the Bilateral France-China Cooperation Program PHC CAI YUANPEI 2018-41475SH.