Piezoelectric Energy Harvesting Based on Multiaxial Ferroelectrics by Precise Molecular Design

Ferroelectrics, as piezoelectric materials with reversal polarization, have great appeal in energy signal harvesting and conversion. Their polarization and piezoelectricity are widely used in various smart devices such as data storage, sensors, solar cells, and self-powered systems. Among them, multiaxial molecular ferroelectrics with multiple equivalent polarization directions are highly preferred for such applications. However, designing and regulating multiaxial molecular ferroelectrics has always been a huge challenge, especially in those with excellent piezoelectric performance. Here, under precise molecular modifications, we successfully designed and regulated four high-temperature multiaxial molecular ferroelectrics, [(CH3)(3)NCH2X]FeBr4 (X = F, Cl, Br, I). More strikingly, piezoresponse force microscopy demonstrates that [(CH3)(3)NCH2F] FeBr4 exhibits a relatively large piezoelectric response comparable with that of polyvinylidene fluoride. This precise molecular design strategy provides an effective means for the acquisition and regulation of multiaxial molecular ferroelectrics, offering new opportunities for modern energy and artificial intelligence.