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

Abstract

Molecule-based ferroelectrics are promising candidates for flexible self-powered power supplies (i.e., piezoelectric generators (PEGs)). Although the large electromechanical conversion coefficients (d₃₃ × g₃₃) 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 d₃₃ × g₃₃. Here, we report a molecule-based ferroelectric [(CH₃)₃NCH₂CH₂Cl][GaBr₄] (1) that exhibits the largest piezoelectric coefficient (∼454 pC N⁻¹) and electromechanical conversion coefficient (4953.1 × 10⁻¹² m² 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.