Recent advances in ferroelectric metal complexes

Ferroelectric materials exhibit spontaneous electric polarization, which can be switched by an external electric field. Owing to their intrinsic abundance of electrical, mechanical, and thermal properties such as pyroelectric and piezoelectric properties, ferroelectric materials can be used in various functional devices, such as data storage devices, sensors, mechanical actuation devices, and other optoelectronic applications. Although molecular-based ferroelectric materials, such as pure organic/inorganic compounds, have piqued significant research interest, unique ferroelectrics based on coordination metal complexes have not been studied in detail. These materials have recently received significant attention because they offer an efficient method for fabricating functional molecular-based materials due to their characteristic intrinsic electronic/spin states. Thus, this review discusses recent advances in the literature on ferroelectricity in metal complexes. We believe that this review will contribute to fabricating novel ferroelectric materials based on metal complexes.