Achievement of a giant electromechanical conversion coefficient in a molecule-based ferroelectric.

Molecule-based ferroelectrics are promising candidates for flexible self-powered power supplies ( i.e. , piezoelectric generators (PEGs)). Although the large electromechanical conversion coefficients ( d 33 × g 33 ) of piezoelectrics are key to enhancing the performance of PEGs in their nonresonant states, it remains a great challenge to obtain molecule-based piezoelectrics with large d 33 × g 33 . Here, we report a molecule-based ferroelectric [(CH 3 ) 3 NCH 2 CH 2 Cl][GaBr 4 ] (1) that exhibits the largest piezoelectric coefficient (∼454 pC N -1 ) and electromechanical conversion coefficient (4953.1 × 10 -12 m 2 N -1 ) among all known free-standing polycrystalline pellets. Notably, the PEG comprising 15 wt% 1 and polydimethylsiloxane (PDMS) achieves a power density of up to 120 μW cm -2 , marking the highest reported power density for ferroelectric@PDMS PEGs to date.