Organometal Trihalide Perovskites with Intriguing Ferroelectric and Piezoelectric Properties

Organometal trihalide perovskites (OTPs) as a new subclass of perovskite materials have recently aroused increasing interest due to their numerous advantages of facile low-temperature processing, tunable bandgaps, diverse compositions, and superior charge transfer dynamics, which have been widely used in various applications. In particular, solar cells composed of these perovskites have made unprecedented progress in just a few years with maximum power conversion efficiency, evolving from 3.8 to 21.6%. In spite of such impressive achievement, a fundamental understanding of intrinsic optoelectronic and physiochemical properties is a key challenge impeding the development of the OTPs. This review article aims to provide a concise overview of the current status of OTPs research, highlighting the unique properties of OTPs, especially ferroelectric and piezoelectric properties, which are vital to photovoltaic and piezoelectric applications but still not adequately explained. Various material synthesis strategies of OTPs are surveyed, exhibiting that the OTPs architecture can serve as a promising and robust platform for opening new horizons in ferroelectric and piezoelectric researches. Several applications, including piezoelectric generators, solar cells, light-emitting diodes, lasers, photodetectors, and water-splitting cells, demonstrate the latent potentialities of OTPs.