Recent progress in the piezoelectricity of molecular ferroelectrics

Molecular ferroelectrics (MOFEs) with excellent piezoelectricity are highly desirable for their easy and environmentally friendly processing, light weight, low processing temperature, and mechanical flexibility. However, although 100 years have passed since the discovery of the ferroelectric effect in 1920, MOFEs with a piezoelectric coefficient comparable to those of the most widely used piezoelectric ceramics, such as barium titanate (∼190 pC N −1 ), have rarely been found. Only in recent years has this situation changed. A series of high-performance piezoelectric MOFEs have been designed and synthesized, approaching or even exceeding some inorganic piezoelectric ceramics. Reviewing on the basis of piezoelectric MOFEs reported, we summarize several methods and strategies to synthesize performance-enhanced and application-aimed piezoelectric MOFEs, with potential as candidates for next-generation medical, micromechanical, and biomechanical devices. This review concluded several recent methods and strategies to synthesize performance-enhanced and application-aimed piezoelectric MOFEs.